The structure of negative symptoms within schizophrenia: implications for assessment

Therapeutic potential of gamma entrainment using sensory stimulation for cognitive symptoms associated with schizophrenia

Schizophrenia is a complex neuropsychiatric disorder with significant morbidity. Treatment options that address the spectrum of symptoms are limited, highlighting the need for innovative therapeutic approaches. Gamma Entrainment Using Sensory Stimulation (GENUS) is an emerging treatment for neuropsychiatric disorders that uses sensory stimulation to entrain impaired oscillatory network activity and restore brain function. Aberrant oscillatory activity often underlies the symptoms experienced by patients with schizophrenia. We propose that GENUS has therapeutic potential for schizophrenia. This paper reviews the current status of schizophrenia treatment and explores the use of sensory stimulation as an adjunctive treatment, specifically through gamma entrainment. Impaired gamma frequency entrainment is observed in patients, particularly in response to auditory and visual stimuli. Thus, sensory stimulation, such as music listening, may have therapeutic potential for individuals with schizophrenia. GENUS holds novel therapeutic potential to improve the lives of individuals with schizophrenia, but further research is required to determine the efficacy of GENUS, optimize its delivery and therapeutic window, and develop strategies for its implementation in specific patient populations.

Brain Age Gap in Early Illness Schizophrenia and the Clinical High-Risk Syndrome: Associations With Experiential Negative Symptoms and Conversion to Psychosis

BACKGROUND AND HYPOTHESIS

Brain development/aging is not uniform across individuals,spawning efforts to characterize brain age from a biological perspective to model the effects of disease and maladaptive life processes on the brain. The brain age gap represents the discrepancy between estimated brain biological age and chronological age (in this case, based on structural magnetic resonance imaging, MRI). Structural MRI studies report an increased brain age gap (biological age > chronological age) in schizophrenia, with a greater brain age gap related to greater negative symptom severity. Less is known regarding the nature of this gap early in schizophrenia (ESZ), if this gap represents a psychosis conversion biomarker in clinical high-risk (CHR-P) individuals, and how altered brain development and/or agingmap onto specific symptom facets.

STUDY DESIGN

Using structural MRI, we compared the brain age gap among CHR-P (n = 51), ESZ (n = 78), and unaffected comparison participants (UCP; n = 90), and examined associations with CHR-P psychosis conversion (CHR-P converters n = 10; CHR-P non-converters; n = 23) and positive and negative symptoms.

STUDY RESULTS

ESZ showed a greater brain age gap relative to UCP and CHR-P (Ps < .010). CHR-P individuals who converted to psychosis showed a greater brain age gap (P = .043) relative to CHR-P non-converters. A larger brain age gap in ESZ was associated with increased experiential (P = .008), but not expressive negative symptom severity.

CONCLUSIONS

Consistent with schizophrenia pathophysiological models positing abnormal brain maturation, results suggest abnormal brain development is present early in psychosis. An increased brain age gap may be especially relevant to motivational and functional deficits in schizophrenia.

Reward anticipation-related neural activation following cued reinforcement in adults with psychotic psychopathology and biological relatives

BACKGROUND

Schizophrenia is associated with hypoactivation of reward sensitive brain areas during reward anticipation. However, it is unclear whether these neural functions are similarly impaired in other disorders with psychotic symptomatology or individuals with genetic liability for psychosis. If abnormalities in reward sensitive brain areas are shared across individuals with psychotic psychopathology and people with heightened genetic liability for psychosis, there may be a common neural basis for symptoms of diminished pleasure and motivation.

METHODS

We compared performance and neural activity in 123 people with a history of psychosis (PwP), 81 of their first-degree biological relatives, and 49 controls during a modified Monetary Incentive Delay task during fMRI.

RESULTS

PwP exhibited hypoactivation of the striatum and anterior insula (AI) during cueing of potential future rewards with each diagnostic group showing hypoactivations during reward anticipation compared to controls. Despite normative task performance, relatives demonstrated caudate activation intermediate between controls and PwP, nucleus accumbens activation more similar to PwP than controls, but putamen activation on par with controls. Across diagnostic groups of PwP there was less functional connectivity between bilateral caudate and several regions of the salience network (medial frontal gyrus, anterior cingulate, AI) during reward anticipation.

CONCLUSIONS

Findings implicate less activation and connectivity in reward processing brain regions across a spectrum of disorders involving psychotic psychopathology. Specifically, aberrations in striatal and insular activity during reward anticipation seen in schizophrenia are partially shared with other forms of psychotic psychopathology and associated with genetic liability for psychosis.

Enhanced Punishment Responses in Patients With Schizophrenia: An Event-Related Potential Study

It is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia. Reduced reward anticipation has been suggested as a core symptom of schizophrenia. The Monetary Incentive Delay Task (MID) is frequently used to detect reward anticipation. The present study aims to evaluate the amplitude and latency of event-related potential (ERP) P300 in patients with schizophrenia (SCH) compared to healthy controls during the MID task. Twenty patients with SCH and 21 demographically matched healthy controls (HC) were included in the study. ERP P300 amplitude and latency values were compared between groups using an MID task in which reward and loss cues were presented. Relations between P300 and clinical facets were investigated in the patient group. SCH group had enhanced mean P300 amplitudes and delayed peak latency in the punishment condition compared with HC. These higher responses were also associated with negative symptoms. SCH group showed altered reward processing as being more sensitive to loss of reward conditions as firstly evidenced by electrophysiological methods, possibly due to abnormality in various systems including social withdrawal, social defeat, and behavioral inhibition system.

Is it more effective for anhedonia and avolition? A systematic review and meta-analysis of non-invasive brain stimulation interventions for negative symptoms in schizophrenia

BACKGROUND

Noninvasive brain stimulation (NIBS) techniques are a promising tool for treating the negative symptoms of schizophrenia. Growing evidence suggests that different dimensions of negative symptoms have partly distinct underlying pathophysiological mechanisms. Previous randomized controlled trials (RCTs) have shown inconsistent impacts of NIBS across dimensions.

OBJECTIVE

This systematic review and meta-analysis evaluated the effects of NIBS on general negative symptoms, and on specific domains, including blunted affect, alogia, asociality, anhedonia, and avolition.

DATA SOURCES

PubMed, Web of Science, Embase, Cochrane CENTRAL, PsycINFO, OpenGrey, and Clinicaltrials.gov from the first date available to October, 2023.

RESULTS

Among 1049 studies, we identified eight high-quality RCTs. NIBS significantly affects general negative symptoms (SMD = -0.54, 95% CI [-0.88, -0.21]) and all five domains (SMD = -0.32 to -0.63). Among dimensions, better effects have been shown for improvement of avolition (SMD = -0.47, 95% CI [-0.81, -0.13]) and anhedonia (SMD = -0.63, 95% CI [-0.98, -0.28]). Subgroup analyses of studies that applied once daily stimulation or >10 sessions showed significantly reduced negative symptom severity.

CONCLUSION

NIBS exerts distinct effects across multiple dimensions of negative symptom, with treatment effects related to stimulation frequency and total sessions. These results need to be confirmed in dedicated studies.

Validity and Reliability Study of Turkish Version of Clinical Assessment Interview for Negative Symptoms (CAINS)

Introduction

This study aims to translate and investigate the validity and reliability of the Turkish version of the Clinical Assessment Interview for Negative Symptoms (CAINS), which has additional features compared to other scales in assessing negative symptoms in patients with schizophrenia.

Methods

The Turkish version of CAINS was constructed upon an initial translation to Turkish, and an English back translation of the scale was later conducted. The patients diagnosed with schizophrenia (n=79) according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria were administered the Turkish version of CAINS, the Positive and Negative Syndrome Scale (PANSS), the Scale for the Assessment of Negative Symptoms (SANS), the Scale for the Assessment of Positive Symptoms (SAPS), the Calgary Depression Scale for Schizophrenia (CDSS), the Clinical Global Impression Scale (CGI), the Global Assessment of Functioning Scale (GAF) and the Simpson-Angus Extrapyramidal Side Effects Assessment Scale (SAS). In addition, two interviewers assessed the video recordings of 11 patients for reliability analysis.

Results

Inter-rater reliability was found to be high (intraclass correlation coefficient (ICC): 0.831). Exploratory and confirmatory factor analyses indicated that Cronbach's alpha was 0.956 for the full scale, and the two-dimensional structure explained the scale better. In convergent validity analyses, CAINS overall scores correlated significantly with the SANS total score (r=0,932) and PANSS negative score (r=0,902). In discriminant validity analyses, CAINS overall scores markedly correlated with the SAPS total (r=0,615), PANSS positive (r=0,497) and PANSS general psychopathology (r=0,737) scores. Additionally, when CGI and GAF scores were considered covariant, the significant correlation of CAINS total scores with the SANS total and PANSS negative scores continued; however, the correlation with PANSS positive score was prominently reduced, and the correlation with PANSS general psychopathology disappeared.

Conclusion

The Turkish version of the CAINS appears to be a valid and reliable tool with strong psychometric properties in a sample consisting of patients with schizophrenia.

Convergent and divergent genes expression profiles associated with brain-wide functional connectome dysfunction in deficit and non-deficit schizophrenia

Deficit schizophrenia (DS) is a subtype of schizophrenia characterized by the primary and persistent negative symptoms. Previous studies have identified differences in brain functions between DS and non-deficit schizophrenia (NDS) patients. However, the genetic regulation features underlying these abnormal changes are still unknown. This study aimed to detect the altered patterns of functional connectivity (FC) in DS and NDS and investigate the gene expression profiles underlying these abnormal FC. The study recruited 82 DS patients, 96 NDS patients, and 124 healthy controls (CN). Voxel-based unbiased brain-wide association study was performed to reveal altered patterns of FC in DS and NDS patients. Machine learning techniques were used to access the utility of altered FC for diseases diagnosis. Weighted gene co-expression network analysis (WGCNA) was employed to explore the associations between altered FC and gene expression of 6 donated brains. Enrichment analysis was conducted to identify the genetic profiles, and the spatio-temporal expression patterns of the key genes were further explored. Comparing to CN, 23 and 20 brain regions with altered FC were identified in DS and NDS patients. The altered FC among these regions showed significant correlations with the SDS scores and exhibited high efficiency in disease classification. WGCNA revealed associations between DS/NDS-related gene expression and altered FC. Additionally, 22 overlapped genes, including 12 positive regulation genes and 10 negative regulation genes, were found between NDS and DS. Enrichment analyses demonstrated relationships between identified genes and significant pathways related to cellular response, neuro regulation, receptor binding, and channel activity. Spatial and temporal gene expression profiles of SCN1B showed the lowest expression at the initiation of embryonic development, while DPYSL3 exhibited rapid increased in the fetal. The present study revealed different altered patterns of FC in DS and NDS patients and highlighted the potential value of FC in disease classification. The associations between gene expression and neuroimaging provided insights into specific and common genetic regulation underlying these brain functional changes in DS and NDS, suggesting a potential genetic-imaging pathogenesis of schizophrenia.

Reduced Reward Processing in Schizophrenia: A Comprehensive EEG Event-Related Oscillation Study

It is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia (SZ). Reduced reward anticipation has been suggested as a core symptom of SZ. The present study aims to evaluate the event-related oscillations (EROs) delta, theta, alpha, beta, and gamma in patients with SZ during the Monetary Incentive Delay (MID) task, which elicits the neural activity of reward processing. Twenty-one patients with SZ and twenty-two demographically matched healthy controls were included in the study. EROs were compared between groups and correlation analyses were conducted to determine a possible relationship between clinical scores and ERO values. Compared with healthy controls, the SZ group had reduced (1) delta and theta amplitudes in the reward condition (2) total beta and non-incentive cue-related beta amplitudes, and (3) incentive cue-related frontal gamma amplitudes. These reductions can be interpreted as impaired dopaminergic neurotransmission and disrupted cognitive functioning in the reward processing of SZ. In contrast, SZ patients showed higher incentive cue-related theta and occipital gamma amplitudes compared to controls. These increments may reflect negative symptoms in SZ. Moreover, theta amplitudes showed a negative correlation with Calgary Depression Scale for Schizophrenia scores and a positive correlation with attentional impulsivity. This is the first study showing the impairments of SZ patients in EROs from delta to gamma frequency bands compared with healthy controls during reward anticipation. Being the first comprehensive study, our results can be interpreted as providing evidence for disrupted brain dynamics in the reward processing of SZ studied by EROs. It may become possible to help patients' wellness by improving our understanding of reward processing in schizophrenia and developing innovative rehabilitation treatments based on these findings.

The longitudinal structure of negative symptoms in treatment resistant schizophrenia

BACKGROUND AND HYPOTHESIS

The negative symptoms of schizophrenia are strong prognostic factors but remain poorly understood and treated. Five negative symptom domains are frequently clustered into the motivation and pleasure (MAP) and emotional expression (EE) 'dimensions', but whether this structure remains stable and behaves as a single entity or not remains unclear.

STUDY DESIGN

We examined a cohort of 153 patients taking clozapine for treatment-resistant schizophrenia in a regional mental health clinic. Patients were assessed longitudinally over a mean period of 45 months using validated scales for positive, negative and mood symptoms. Network analyses were performed to identify symptom 'communities' and their stability over time. The influence of common causes of secondary negative symptoms as well as centrality measures were also examined.

STUDY RESULTS

Across patients at baseline, two distinct communities matching the clinical domains of MAP and EE were found. These communities remained highly stable and independent over time. The communities remained stabled when considering psychosis, depression, and sedation severity, and these causes of secondary negative symptoms were clustered into the MAP community. Centrality measures also remained stable over time, with similar centrality measures across symptoms.

CONCLUSIONS

Our results suggest that MAP and EE are independent dimensions that remain highly stable over time in chronic schizophrenia patients treated with clozapine. Common causes of secondary negative symptoms mapped onto the MAP dimension. Our results emphasise the need for clinical trials to address either MAP or EE, and that treating causes of secondary negative symptoms may improve MAP.

The relationship between negative symptoms and MATRICS neurocognitive domains: A meta-analysis and systematic review

BACKGROUND

Negative symptoms (NS) are a core symptom domain in schizophrenia spectrum disorders and are associated with poorer social and vocational functioning, and with increased likelihood and durations of hospital admission. NS are not well understood, limiting available interventions. However, numerous studies have reported associations between neurocognitive domains and NS severity. Thus, one promising area in understanding NS is in relation to neurocognition. Currently, the specificity of the relationship between NS and neurocognition is unknown, meaning that there is no consensus regarding which neurocognitive domain is most strongly associated with NS. There is a need to systematically examine the relationship between NS and various neurocognitive domains within study samples.

METHODS

A systematic search of Ovid PsycINFO, Ovid MEDLINE and Web of Science was performed for articles published since 2004 (year of MATRICS Consensus publication). Inclusion criteria were: 1) individuals with schizophrenia spectrum disorders, first episode psychosis or clinical high risk 2) assessed all six MATRICS neurocognitive domains (processing speed, attention, working memory, verbal learning & memory, visual learning & memory, reasoning & problem solving), 3) reported correlations between all six MATRICS neurocognitive domains and global NS. A three-level random effects hierarchical meta-analysis was performed to assess the relationship between NS (global, expressive, and experiential dimensions) and the six MATRICS neurocognitive domains.

RESULTS

21 studies were included in the review (n = 3619). All MATRICS neurocognitive domains had small significant correlations with global NS (r = -0.16 to -0.20, p < 0.0001). This relationship was significantly moderated by diagnosis and the moderating effect of sex/ gender trended on significance. Analysis of a subset of the studies revealed that MATRICS neurocognitive domains also had small significant correlations with the two NS dimensions, expressive and experiential. Correlations were stronger with the expressive NS dimension.

CONCLUSIONS

This review is novel in assessing the relationship between multiple neurocognitive domains and NS within the same sample, by synthesizing close to two decades of research. Our results suggest that there is a non-specific relationship between neurocognition and NS, and that expressive NS may have a stronger relationship with neurocognitive functioning-based on the MATRICS classification of neurocognition and the neurocognitive assessments used in the included studies. This has implications on our understanding of NS and neurocognition, as well as their treatments. As we gain better understanding of the directionality of the NS-cognition relationship, it could suggest that NS, particularly in the expressive domain, could be improved by targeting cognition globally or that neurocognitive treatments could be more effective if NS are addressed first. Further implications of these results are discussed.

A neuromarker for deficit syndrome in schizophrenia from a combination of structural and functional magnetic resonance imaging

AIM

Deficit schizophrenia (DS), defined by primary and enduring negative symptoms, has been proposed as a promising homogeneous subtype of schizophrenia. It has been demonstrated that unimodal neuroimaging characteristics of DS were different from non-deficit schizophrenia (NDS), however, whether multimodal-based neuroimaging features could identify deficit syndrome remains to be determined.

METHODS

Functional and structural multimodal magnetic resonance imaging of DS, NDS and healthy controls were scanned. Voxel-based features of gray matter volume, fractional amplitude of low-frequency fluctuations, and regional homogeneity were extracted. The support vector machine classification models were constructed using these features separately and jointly. The most discriminative features were defined as the first 10% of features with the greatest weights. Moreover, relevance vector regression was applied to explore the predictive values of these top-weighted features in predicting negative symptoms.

RESULTS

The multimodal classifier achieved a higher accuracy (75.48%) compared with the single modal model in distinguishing DS from NDS. The most predictive brain regions were mainly located in the default mode and visual networks, exhibiting differences between functional and structural features. Further, the identified discriminative features significantly predicted scores of diminished expressivity factor in DS but not NDS.

CONCLUSIONS

The present study demonstrated that local properties of brain regions extracted from multimodal imaging data could distinguish DS from NDS with a machine learning-based approach and confirmed the relationship between distinctive features and the negative symptoms subdomain. These findings may improve the identification of potential neuroimaging signatures and improve the clinical assessment of the deficit syndrome.

Two and five-factor models of negative symptoms in schizophrenia are differentially associated with trait affect, defeatist performance beliefs, and psychosocial functioning

Recent factor analytic evidence supports both two-factor (motivation and pleasure, MAP; diminished expression, EXP) and five-factor (anhedonia, asociality, avolition, blunted affect, alogia) conceptualizations of negative symptoms. However, it is unclear whether these two conceptualizations of the latent structure of negative symptoms have differential associations with external correlates. The current study evaluated external correlates of the two- and five-factor structures by examining associations with variables known to have critical relations with negative symptoms: trait affect, defeatist performance beliefs, neurocognition, and community-based psychosocial functioning. Participants included a total of 245 outpatients diagnosed with schizophrenia who were rated on the Brief Negative Symptom Scale and completed a battery of additional measures during periods of clinical stability. These additional measures included the Positive and Negative Affect Schedule, Defeatist Performance Beliefs scale, MATRICS Consensus Cognitive Battery, and Level of Function Scale. Pearson correlations indicated differential patterns of associations between the BNSS scores and the external correlates. Support for the two-factor model was indicated by a stronger association of MAP with positive affect and psychosocial functioning, compared to EXP with neurocognition. Significance tests examining a differential magnitude of associations showed that the two-dimension negative symptom structure masked unique correlational relationships among the five negative symptom domains with neurocognition and social/vocational community functioning and captured unique patterns of correlation with trait affect. Support for the five-factor model was shown by a stronger association between Blunted Affect with Attention/Vigilance, and stronger associations between Avolition, Anhedonia, and Asociality with psychosocial functioning. Results offer support for both the two-dimension and five-domain model of negative symptoms as well as a hierarchical two-dimensions-five-domains model of negative symptoms. Findings may have implications for diagnostic criteria and descriptions of the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5), as well as possible treatment targets of negative symptoms.

Correlations between Negative Symptoms and Cognitive Deficits in Individuals at First Psychotic Episode or at High Risk of Psychosis: A Systematic Review

The present review aims to identify correlations between negative symptoms (NS) and deficits in neurocognition and social cognition in subjects with first-episode psychosis (FEP) and at-high-risk populations (HR). A systematic search of the literature published between 1 January 2005 and 31 December 2022 was conducted on PubMed, Scopus, and PsycInfo. Out of the 4599 records identified, a total of 32 studies met our inclusion/exclusion criteria. Data on a total of 3086 FEP and 1732 HR were collected. The available evidence shows that NS correlate with executive functioning and theory of mind deficits in FEP subjects, and with deficits in the processing speed, attention and vigilance, and working memory in HR subjects. Visual learning and memory do not correlate with NS in either FEP or HR subjects. More inconsistent findings were retrieved in relation to other cognitive domains in both samples. The available evidence is limited by sample and methodological heterogeneity across studies and was rated as poor or average quality for the majority of included studies in both FEP and CHR populations. Further research based on shared definitions of first-episode psychosis and at-risk states, as well as on more recent conceptualizations of negative symptoms and cognitive impairment, is highly needed.

Dysfunction of visual novelty detection in physical but not social anhedonia in a non-clinical sample

Background/objective

Despite its obvious motivational impairment, anhedonia as a transdiagnostic psychopathological construct is accompanied by deficits in attention function. Previous studies have identified voluntary attention anomalies in anhedonia, but its involuntary attention has received less study.

Method

Using a visual novelty oddball task, the current event-related potential study assessed electrophysical correlates underlying mismatch detection in anhedonia with a non-clinical sample. Well-matched healthy control (N = 28; CNT), social anhedonia (N = 27; SA), and physical anhedonia (N = 26; PA) groups were presented standard, target, and perceptually novel stimuli while their EEG was recording.

Results

The PA group relative to the CNT group exhibited a reduced N2 to novel stimuli but not to target stimuli. In contrast, the SA group as compared to the other two groups showed comparable N2 responses to both target and novel stimuli. Control analyses indicated that these patterns were unaffected by depression symptoms.

Conclusions

These findings suggest that anhedonia is a heterogenous construct associated with impairments in early detection of visual novelty in physical but not social anhedonia, highlighting that dysfunction in involuntary attention may play a mediating role in the development, maintenance, and consequences of anhedonia-related psychopathology.

The structure stability of negative symptoms: longitudinal network analysis of the Brief Negative Symptom Scale in people with schizophrenia

BACKGROUND

The structure of negative symptoms of schizophrenia is still a matter of controversy. Although a two-dimensional model (comprising the expressive deficit dimension and the motivation and pleasure dimension) has gained a large consensus, it has been questioned by recent investigations.

AIMS

To investigate the latent structure of negative symptoms and its stability over time in people with schizophrenia using network analysis.

METHOD

Negative symptoms were assessed in 612 people with schizophrenia using the Brief Negative Symptom Scale (BNSS) at baseline and at 4-year follow-up. A network invariance analysis was conducted to investigate changes in the network structure and strength of connections between the two time points.

RESULTS

The network analysis carried out at baseline and follow-up, supported by community detection analysis, indicated that the BNSS's items aggregate to form four or five distinct domains (avolition/asociality, anhedonia, blunted affect and alogia). The network invariance test indicated that the network structure remained unchanged over time (network invariance test score 0.13; P = 0.169), although its overall strength decreased (6.28 at baseline, 5.79 at follow-up; global strength invariance test score 0.48; P = 0.016).

CONCLUSIONS

The results lend support to a four- or five-factor model of negative symptoms and indicate overall stability over time. These data have implications for the study of pathophysiological mechanisms and the development of targeted treatments for negative symptoms.

The other side of the social interaction: Theory of mind impairments in people with schizophrenia are linked to other people's difficulties in understanding them

BACKGROUND

People with schizophrenia (SZ) often present with theory of mind (ToM) deficits and with speech production deficits. While a link has been established between ToM abilities and symptoms of thought disorder, much less is known about other aspects of speech production in SZ.

STUDY DESIGN

This is a case-control study in which 25 stable outpatients with recent-onset SZ (27.1 years, 22 men) and 22 matched healthy controls (25.6 years, 16 men) performed a collaborative, verbal production task with a real interaction partner. Blind raters scored how easy participants made it to understand them (Facility ratings), how interesting they were to listen to (Interest ratings) and how expressive they were (Expressivity ratings). ToM was assessed with the Combined Stories Test and Sarfati's cartoon task. Symptoms were assessed with the PANSS five-factor version.

STUDY RESULTS

Compared to healthy controls, SZ received significantly lower ratings for all three aspects of their verbal productions (Facility, Interest and Expressivity), despite the raters being blind to group membership. Interestingly, the Facility ratings were linked to ToM performance in the SZ group, which suggest that SZ participants who have difficulties understanding others (ToM deficits) also make it harder for others to understand them. Other notable findings include a strong link between the Expressivity ratings and the Interest ratings for both groups, and significant correlations between the Facility ratings and Cognitive/Disorganisation symptoms, and between the Expressivity ratings and both Negative and Depression/Anxiety symptoms in SZ.

CONCLUSION

Studying speech production during real, collaborative social interactions could help move beyond the individual approach to SZ deficits, making it possible to involve the interaction partners to promote more efficient communication for people with schizophrenia.

Negative symptoms in schizophrenia: Newly emerging measurements, pathways, and treatments

The negative symptoms of schizophrenia, which often appear earlier than any other symptom, are prominent and clinically relevant in the majority of patients. As a result, interest in their treatment has increased. Patients who exhibit significant negative symptoms have worse functional outcomes than those without, resulting in impairments in occupational, household, and recreational functioning, as well as difficulties in relationships. Yet treatment with currently available medications does not lead to any significant improvements in this core component of schizophrenia. An increased understanding of the pathophysiology underlying negative symptoms and the discovery of novel treatments that do not directly target dopamine offer the potential to develop therapies that may reduce negative symptoms and increase quality of life for patients. The current article will discuss the impact of negative symptoms, outline current measurement tools for the assessment of negative symptoms, and examine how these measures may be improved. Insights into the neural circuitry underlying negative symptoms will be discussed, and promising targets for the development of effective treatments for these symptoms will be identified. As more prospective, large-scale, randomized studies focus on the effects of treatments on negative symptoms, progress in this area is foreseeable. However, improvements in clinical assessment instruments, a better understanding of the underlying neural mechanisms, development of novel treatments with varied targets, and a greater focus on personalized treatment are all important to produce significant benefits for patients with negative symptoms of schizophrenia.

Electrophysiological Correlates of Reward Anticipation in Subjects with Schizophrenia: An ERP Microstate Study

The current study aimed to investigate alterations of event-related potentials (ERPs) microstate during reward anticipation in subjects with schizophrenia (SCZ), and their association with hedonic experience and negative symptoms. EEG data were recorded in thirty SCZ and twenty-three healthy controls (HC) during the monetary incentive delay task in which reward, loss and neutral cues were presented. Microstate analysis and standardized low-resolution electromagnetic tomography (sLORETA) were applied to EEG data. Furthermore, analyses correlating a topographic index (the ERPs score), calculated to quantify brain activation in relationship to the microstate maps, and scales assessing hedonic experience and negative symptoms were performed. Alterations in the first (125.0-187.5 ms) and second (261.7-414.1 ms) anticipatory cue-related microstate classes were observed. In SCZ, reward cues were associated to shorter duration and earlier offset of the first microstate class as compared to the neutral condition. In the second microstate class, the area under the curve was smaller for both reward and loss anticipation cues in SCZ as compared to HC. Furthermore, significant correlations between ERPs scores and the anticipation of pleasure scores were detected, while no significant association was found with negative symptoms. sLORETA analysis showed that hypo-activation of the cingulate cortex, insula, orbitofrontal and parietal cortex was detected in SCZ as compared to HC. Abnormalities in ERPs could be traced already during the early stages of reward processing and were associated with the anticipation of pleasure, suggesting that these dysfunctions might impair effective evaluation of incoming pleasant experiences. Negative symptoms and anhedonia are partially independent results.

Residual experiential symptoms mediate the effect of expressive symptoms over the social functioning in remitted schizophrenia

Context

Impairment in social functioning had been consistently found in remitted schizophrenia; yet, predictors of social dysfunction had been hardly explored and intervention trials had rarely included remitted schizophrenia.

Methods

60 subjects with schizophrenia (diagnosed based on DSM5), currently in remission (SAPS and SANS global rating ≤2, for a minimum period of 12 weeks) and 46 age and gender-matched healthy controls were recruited after obtaining informed consent. The socio-demographic details, illness characteristics, depressive symptoms, positive and negative symptoms [using Scale for assessment of positive symptoms (SAPS), and scale for assessment of negative symptoms (SANS)] were assessed. The Theory of Mind (ToM) score was derived from the ToM tasks of a culturally validated tool, Social Cognition Rating Tools in Indian Setting. The social functioning was assessed using Groningen social disabilities schedule II (GSDSSII).

Results

The mean SAPS summary and SANS summary scores were 3.01 ± 2.99 and 4.32 ± 2.94, respectively. The social functioning was significantly impaired in remitted schizophrenia when compared to healthy controls. In the hierarchical regression, experiential dimension (β =1.941, t = 6.097, P < 0.001), followed by expressive dimension predicted social functioning (explained 70.5% of variance) after controlling for confounders. On mediation analysis, the effect of expressive dimension over the social functioning was significantly mediated by experiential dimension (E = 1.1821, Boot SE = 0.2895, C.I: 0.6934 to 1.7862).

Conclusion

The experiential dimension mediates the effect of expressive dimension over the social dysfunction in remitted schizophrenia. Future studies should focus on targeting the experiential dimension and thereby social functioning.

"Goals in Focus"-a targeted CBT approach for motivational negative symptoms of psychosis: study protocol for a randomized-controlled feasibility trial

BACKGROUND

The reduction of goal-directed behavior is the main characteristic in motivational negative symptoms of psychosis as it accounts for the long-term decline in psychological well-being and psychosocial functioning. However, the available treatment options are largely unspecific and show only small effects on motivational negative symptoms. Interventions that directly target the relevant psychological mechanisms are likely to be more effective. For "Goals in Focus", we translated findings from basic clinical research on mechanisms underlying motivational negative symptoms into a tailored and comprehensive novel psychological outpatient treatment program. With this study, we will test the feasibility of the therapy manual and the trial procedures. We also aim to examine first estimates of the effect size that can be expected from "Goals in Focus" to inform the sample size calculation of a subsequent fully powered trial.

METHODS

Thirty participants diagnosed with a schizophrenia spectrum disorder and at least moderate motivational negative symptoms will be randomly assigned to either 24 sessions of "Goals in Focus" over the course of 6 months (n = 15) or to a 6-month wait-list control group (n = 15). Single-blind assessments will be conducted at baseline (t₀) and 6 months after baseline completion (t₁). Feasibility outcomes include patient recruitment, retention, and attendance rates. Acceptability will be rated by trial therapists and by participants at end of treatment. Primary outcome for effect size estimation is the motivational negative symptom subscale sum score of the Brief Negative Symptom Scale at t₁ corrected for baseline values. Secondary outcomes include psychosocial functioning, psychological well-being, depressive symptoms, expressive negative symptoms, negative symptom factor scores, and goal pursuit in everyday life.

DISCUSSION

The feasibility and acceptability data will be used to improve trial procedures and the "Goals in Focus" intervention where necessary. The treatment effect on the primary outcome will provide the basis for the sample size calculation for a fully powered RCT.

TRIAL REGISTRATION

1) ClinicalTrials.gov, NCT05252039 . Registered on 23 February 2022. 2) Deutsches Register Klinischer Studien, DRKS00018083 . Registered on 28 August 2019.

The structure of apathy symptoms

INTRODUCTION

Apathy is common in many neurological, psychiatric, and medical disorders and is related to a number of important clinical outcomes. Nonetheless, research on apathy is hindered by different ways of defining and measuring it, which has led to heterogeneity in research findings.

METHOD

The current study aimed to investigate the factor structure of apathy symptoms using a novel item pool. We examined whether the use of this item pool has incremental validity above and beyond a widely used measure in predicting cognition and everyday functioning. Participants included 249 informants who reported on an individual with (n = 210) or without (n = 39) a neurological or psychiatric condition.

RESULTS

Results showed the best fitting model of apathy symptoms was a bifactor model with apathy as a general dimension and three specific symptom factors including reduced interest and initiative, reduced emotional and verbal expression, and reduced social engagement. Incremental validity in predicting cognition was demonstrated for this more robust assessment of apathy symptoms.

CONCLUSIONS

Results are most aligned with one set of proposed diagnostic criteria for apathy which differs from other criteria in that it does not distinguish between cognitive and behavioral symptoms and includes a separate social dimension. Future research could aim to replicate this model in additional clinical samples and explore the incremental validity of the newly developed Apathy Symptom Inventory (ASI) in comparison to other recently developed measures.

Validity and reliability of a Chinese version of the self-evaluation of negative symptoms

The negative symptoms of schizophrenia can be present at any clinical stage, but evaluating the negative symptoms always remains challenging. To screen the negative symptoms effectively, self-evaluation should be introduced. To date, professional psychiatrists used almost all of the scales available to screen the negative symptoms but could not obtain an accurate outcome. At the same time, an advanced self-assessment scale is needed to accompany the patients' self-feeling-based treatment strategies to understand their feelings about their symptoms. Hence, Chinese self-evaluation of negative symptoms (SNS) should be introduced in China. This study aims to examine the validity and reliability of the Chinese version of SNS. Two hundred patients with schizophrenia were included in this study and were evaluated entirely with the self-assessed negative symptoms by the Chinese version. The correlation analysis was performed between SNS and the Scale for Assessment of Negative Symptoms (SANS) to assess the criterion validity of SNS for screening negative symptoms. Exploratory factor analysis was used to determine the constructive validity of the SNS. Two senior professional psychiatrists were involved in this assessment based on their clinical experience and capability to define the severity of the negative symptoms. Receiver operating characteristic curve (ROC) analysis was performed to assess the cutoff point of SNS. Cronbach's alpha coefficient and intraclass correlation (ICC) coefficient were used to determine the reliability of SNS. We have the following findings: The Chinese version of SNS demonstrated a significant correlation with the SANS (r = .774, p < .05). Exploratory factor analysis demonstrated that the factor loading varies from .442 to .788. ROC analysis demonstrated that at SNS ≥ 8, the patients demonstrated a mild severity of negative symptoms, and at SNS ≥ 15, the patients demonstrated a severe severity of negative symptoms. Subsequently, 9 < SNS < 14 was defined as a moderate severity of negative symptoms. The Cronbach's alpha and ICC coefficients of the Chinese version SNS were .877 and .774, respectively. Our results showed that the acceptable validity and reliability of the Chinese version of SNS confirmed that SNS is an ideal tool for self-assessment of the negative symptoms in patients with schizophrenia.

Using dimensionality-reduction techniques to understand the organization of psychotic symptoms in persistent psychotic illness and first episode psychosis

Psychotic disorders are highly heterogeneous. Understanding relationships between symptoms will be relevant to their underlying pathophysiology. We apply dimensionality-reduction methods across two unique samples to characterize the patterns of symptom organization. We analyzed publicly-available data from 153 participants diagnosed with schizophrenia or schizoaffective disorder (fBIRN Data Repository and the Consortium for Neuropsychiatric Phenomics), as well as 636 first-episode psychosis (FEP) participants from the Prevention and Early Intervention Program for Psychosis (PEPP-Montreal). In all participants, the Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS) were collected. Multidimensional scaling (MDS) combined with cluster analysis was applied to SAPS and SANS scores across these two groups of participants. MDS revealed relationships between items of SAPS and SANS. Our application of cluster analysis to these results identified: 1 cluster of disorganization symptoms, 2 clusters of hallucinations/delusions, and 2 SANS clusters (asocial and apathy, speech and affect). Those reality distortion items which were furthest from auditory hallucinations had very weak to no relationship with hallucination severity. Despite being at an earlier stage of illness, symptoms in FEP presentations were similarly organized. While hallucinations and delusions commonly co-occur, we found that their specific themes and content sometimes travel together and sometimes do not. This has important implications, not only for treatment, but also for research-particularly efforts to understand the neurocomputational and pathophysiological mechanism underlying delusions and hallucinations.

Efficacy of Serotonin and Dopamine Activity Modulators in the Treatment of Negative Symptoms in Schizophrenia: A Rapid Review

Schizophrenia is among the fifteen most disabling diseases worldwide. Negative symptoms (NS) are highly prevalent in schizophrenia, negatively affect the functional outcome of the disorder, and their treatment is difficult and rarely specifically investigated. Serotonin-dopamine activity modulators (SDAMs), of which aripiprazole, cariprazine, brexpiprazole, and lumateperone were approved for schizophrenia treatment, represent a possible therapy to reduce NS. The aim of this rapid review is to summarize the evidence on this topic to make it readily available for psychiatrists treating NS and for further research. We searched the PubMed database for original studies using SDAM, aripiprazole, cariprazine, brexpiprazole, lumateperone, schizophrenia, and NS as keywords. We included four mega-analyses, eight meta-analyses, two post hoc analyses, and 20 clinical trials. Aripiprazole, cariprazine, and brexpiprazole were more effective than placebo in reducing NS. Only six studies compared SDAMs with other classes of antipsychotics, demonstrating a superiority in the treatment of NS mainly for cariprazine. The lack of specific research and various methodological issues, related to the study population and the assessment of NS, may have led to these partial results. Here, we highlight the need to conduct new methodologically robust investigations with head-to-head treatment comparisons and long-term observational studies on homogeneous groups of patients evaluating persistent NS with first- and second-generation scales, namely the Brief Negative Symptom Scale and the Clinical Assessment Interview for Negative Symptoms. This rapid review can expand research on NS therapeutic strategies in schizophrenia, which is fundamental for the long-term improvement of patients’ quality of life.

Psychosocial and behavioural interventions for the negative symptoms of schizophrenia: a systematic review of efficacy meta-analyses

BACKGROUND

Currently there is no first-line treatment recommended for the negative symptoms of schizophrenia. Psychosocial and behavioural interventions are widely used to reduce the burden of negative symptoms. Meta-analytic studies have summarised the evidence for specific approaches but not compared evidence quality and benefit.

AIM

To review and evaluate the evidence from meta-analytic studies of psychosocial and behavioural interventions for the negative symptoms of schizophrenia.

METHOD

A systematic literature search was undertaken to identify all meta-analyses evaluating psychosocial and behavioural interventions reporting on negative symptom outcomes in people with schizophrenia. Data on intervention, study characteristics, acceptability and outcome were extracted. Risk of bias was evaluated. Results were summarised descriptively, and evidence ranked on methodological quality.

RESULTS

In total, 31 systematic reviews met the inclusion criteria evaluating the efficacy of negative symptom interventions on 33 141 participants. Exercise interventions showed effect sizes (reduction in negative symptoms) ranging from -0.59 to -0.24 and psychological interventions ranging from -0.65 to -0.04. Attrition ranged between 12% to 32%. Across the studies considered heterogeneity varied substantially (range 0-100). Most of the reviews were of very low to low methodological quality. Methodological quality ranking suggested that the effect size for cognitive remediation and exercise therapy may be more robust compared with other approaches.

CONCLUSIONS

Most of the interventions considered had a small-to-moderate effect size, good acceptability levels but very few had negative symptoms as the primary intervention target. To improve the confidence of these effect sizes being replicated in clinical settings future studies should minimise risk of bias.

The Self-Evaluation of Negative Symptoms in Differentiating Deficit Schizophrenia: The Comparison of Sensitivity and Specificity with Other Tools

INTRODUCTION

Psychometric properties of the Self-evaluation of Negative Symptoms (SNS) in subjects with the deficit subtype of schizophrenia (SCZ-D) have not been investigated so far. This study had the following aims: (1) to assess psychometric properties of SNS in subjects with SCZ-D and (2) to explore the usefulness of SNS, in comparison with other clinical characteristics, in screening for SCZ-D.

METHODS

Participants were 82 stable outpatients with schizophrenia, including 40 individuals with SCZ-D and 42 individuals with the non-deficit subtype (SCZ-ND).

RESULTS

Internal consistency was acceptable-to-good in both groups. Factor analysis revealed two dimensions (apathy and emotional). There were significant positive correlations of the SNS total score with the subscore of negative symptoms from the Positive and Negative Syndrome Scale (PANSS) and significant negative correlations with scores of the Social and Occupational Functioning Assessment Scale (SOFAS) in both groups, indicating good convergent validity. The following measures were found to be appropriate screening tools for differentiating SCZ-D and SCZ-ND (p < 0.001): the SNS total score (area under the curve [AUC]: 0.849, cut-off ≥16, sensitivity: 80.0%, specificity: 78.6%), the PANSS subscore of negative symptoms (AUC: 0.868, cut-off ≥11, sensitivity: 90.0%, specificity: 78.6%), and the SOFAS (AUC: 0.779, cut-off ≤59, sensitivity: 69.2%, specificity: 82.5%). Also, adding the SOFAS (cut-off ≤59) to the SNS (cut-off: ≥16) further improved sensitivity and specificity (AUC: 0.898, p < 0.001, sensitivity = 87.5%, specificity = 82.2%). Cognitive performance and age of psychosis onset were not found to be suitable measures for differentiating SCZ-D and SCZ-ND.

CONCLUSION

The present findings indicate that the SNS has good psychometric properties in subjects with SCZ-D and those with SCZ-ND. Moreover, the SNS, the PANSS, and the SOFAS might be used as screening tools for SCZ-D.

Negative symptoms in drug-naive patients with a first-episode psychosis (FEP)

INTRODUCTION

Negative symptoms are nuclear features of schizophrenia that may be present from the onset of the disease. In recent years, it has been described 2 subdomains of negative symptoms: experiential and expressive deficits. The aim of the study is to examine the relationship between negative symptoms and demographic and clinical variables in patients with first-episode psychosis. Also, to explore whether there are differences in the association among these variables and negative symptoms when divided into both subdomains.

MATERIAL AND METHODS

A cross-sectional study was performed in 160 patients (52 females and 108 males) with a diagnosis of a first episode psychosis. A questionnaire was administered to collect demographic and clinical variables.

RESULTS

A backward stepwise linear regressions analysis was performed in order to observe potential associations between demographic and clinical variables and the presence of negative symptoms. All three models are predicted by worse PSP score, a higher CDSS, a higher disorganized factor score and a lower excited factor score. A longer duration of untreated psychosis (DUP) is associated to a higher score in the experiential deficit subdomain only.

CONCLUSIONS

Our work highlights some clinical and phenomenological differences between experiential and expressive deficits. We think that taking into account both subdomains in future studies may lead to more accurate clinical assessment and interventions.

Aerobic and Postural Strength Exercise Benefits in People with Schizophrenia

BACKGROUND

This study aimed to evaluate the effect of two different types of physical intervention on sedentary behavior and clinical changes in people with schizophrenia.

METHOD

This is a clinical trial including people with schizophrenia in regular outpatient care who realized a 3-month exercise protocol and were separated into two groups: aerobic physical intervention (API) and postural physical intervention (PPI). All participants performed an assessment of (a) functional capacity through a 6 min walk test (6MWT), (b) flexibility using Well's bench, (c) disease severity using the Brief Psychiatric Rating Scale (BPRS), (d) quality of life using the SF-36 Questionnaire and (e) physical activity using the Simple Physical Activity Questionnaire (SIMPAQ).

RESULTS

Thirty-eight patients with schizophrenia completed the intervention (24 patients in API and 14 patients in PPI). Regarding sedentary behavior, there was an improvement in the API group in the time exercising and in the PPI group concerning time in bed, time walking and exercising. Regarding quality of life, there was an improvement in the API group (functional capacity) and in the PPI group, there was an improvement in physical limitation, pain and emotional limitations. In the API group, there was an improvement in BMI (body mass index), diastolic blood pressure and systolic blood pressure. Functional capacity was improved only in the PPI group. There was no change in flexibility and disease severity.

CONCLUSIONS

The study demonstrated a change response in the physical and mental aspects in people with schizophrenia after a change in sedentary behavior.

Altered intrinsic cerebellar-cerebral functional connectivity is related to negative symptoms in patients with first-episode psychosis

BACKGROUND

Negative symptoms in schizophrenia include cognitive and affective dysfunction, such as diminished expression and amotivation. Although the cerebellar posterior hemisphere and vermis are involved in cognitive and affective functioning, previous studies on the neural mechanism of negative symptoms have mostly been confined to the cerebral cortex. This study aimed to investigate whether resting-state cerebellar-cerebral functional connectivity (FC) is altered in first-episode psychosis (FEP) patients and whether this connectivity is related to negative symptoms.

METHODS

Resting-state functional magnetic resonance images were obtained from 38 FEP patients and 100 healthy controls (HCs). Using the posterior hemisphere and vermis of the cerebellum as seeds, whole-brain FC was compared between FEP patients and HCs. As cerebellar-parietal cortex connectivity is associated with negative symptoms and sociocognitive dysfunctions in schizophrenia patients, its correlation with negative symptoms was explored in FEP patients.

RESULTS

FEP patients showed hyperconnectivity between the cerebellum and bilateral frontal pole (FP), occipital pole, fusiform gyrus, right lingual gyrus, central opercular cortex, anterior middle temporal gyrus, precuneus, and subcallosal cortex. Hypoconnectivity was found between the cerebellum and left FP, right anterior supramarginal gyrus (aSMG), and cerebellum crus I. FC between the left crus II and right aSMG was negatively correlated with the severity of negative symptoms and diminished expression.

CONCLUSIONS

Altered FC between the cerebellum and cerebral regions related to cognitive, affective, and sensory processing was found in FEP patients and was connected to negative symptoms. These results suggest that the cerebellum plays a role in the pathophysiology of negative symptoms in schizophrenia.

Preliminary evidence that fatigue contributes to anhedonia in stable individuals diagnosed with schizophrenia

OBJECTIVES

Anhedonia and fatigue are trans-diagnostic symptoms commonly observed in schizophrenia. Anhedonia is a core negative symptom with a strong relationship with depression and is associated with diminished global functioning. Similarly, fatigue is also associated to depression and research across psychiatric illnesses indicate that fatigue may persist even when primary symptoms are treated. Although fatigue is common in people diagnosed with schizophrenia, it is under studied within this population. The objective of this exploratory study was to investigate the association of fatigue and anhedonia by controlling for depression in a sample of individuals diagnosed with schizophrenia.

METHOD

Fifty-one stable individuals diagnosed with schizophrenia from the University Department of Adult Psychiatry in Montpellier took part in this study. Participants completed questionnaires on fatigue impact and depression, and were assessed for symptom severity. Following data collection, statistical analyses were conducted in order to explore associations between clinical variables and fatigue impact. Based on the results obtained, a hierarchical linear regression was conducted in order to investigate whether fatigue impact contributed to the variance of negative symptoms.

RESULTS

The hierarchical linear regression indicated that when controlling for depression, fatigue impact contributes to ~20% of the variance of anhedonia. Together the social impact of fatigue and depression contribute to 24% of the variation of anhedonia.

CONCLUSION

To the best of our knowledge, this exploratory study is the first to investigate and show that fatigue impact may contribute to anhedonia. We recommend further research to investigate fatigue, its impact on symptomatology, and better categorization of negative symptoms in hopes of developing targeted fatigue treatment interventions.

The relative contributions of insight and neurocognition to intrinsic motivation in schizophrenia

Intrinsic motivation was described as the mental process of pursuing a task or an action because it is enjoyable or interesting in itself and was found to play a central role in the determination of the functional outcome of schizophrenia. Neurocognition is one of the most studied determinants of intrinsic motivation in clinically stable schizophrenia while little is known about the role of insight. Following this need we decided to focus on the contribution of different aspects of insight and of neurocognition to intrinsic motivation in a large sample (n = 176) of patients with stable schizophrenia. We performed three hierarchical linear regressions from which resulted that, among different insight aspects, the ability to correctly attribute signs and symptoms to the mental disorder made the strongest contribution to intrinsic motivation. Neurocognition, also, was significantly related to intrinsic motivation when analyzed simultaneously with insight. Moreover, even after accounting for sociodemographic and clinical variables significantly correlated with intrinsic motivation, the relationship between insight and neurocognition and intrinsic motivation remained statistically significant. These findings put the emphasis on the complex interplay between insight, neurocognition, and intrinsic motivation suggesting that interventions targeting both insight and neurocognition might possibly improve this motivational deficit in stable schizophrenia should.

Primary and secondary negative symptoms severity and the use of psychiatric care resources in schizophrenia spectrum disorders: A 3-year follow-up longitudinal retrospective study

Negative symptoms represent one of the core features of schizophrenia spectrum disorders (SSD), strongly correlated with low remission rates, poor real-world functioning, and worse quality of life. Despite the body of evidence attesting the role of negative symptoms in determining worse outcomes in SSD, few studies have directly investigated their impact on the use of psychiatric services and even fewer research have examined the differential impact between primary versus secondary negative symptoms. The present study aims to investigate whether SSD subjects with high levels of primary and of secondary negative symptoms at an index hospitalization show a different use of psychiatric services in the subsequent 3 years. A total of 429 subjects were included in the study. Results show that SSD patients with high levels of negative symptoms are characterized by an overall greater use of high-cost resources, with more admissions in the hospital acute care psychiatric ward and in high intensity residential inpatient services. Moreover, while primary negative symptoms appear to play a role in determining a greater use of psychiatric services, high levels of secondary negative symptoms are associated with an increased use of most psychiatric resources, especially of high-cost ones. In conclusion, negative symptoms have a relevant impact on the pattern of psychiatric resources utilization in SSD patients. While scientific research continues to look for effective treatments for primary negative symptoms, clinicians should pay particular attention to secondary negative symptoms, as these also have important consequences but may benefit from appropriate treatment.

The relationship between negative symptoms, social cognition, and social functioning in patients with first episode psychosis

INTRODUCTION

Social functioning is severely affected in psychotic disorders. Negative symptoms and social cognition seem to play an important role in social functioning, although the preponderance and relationship between these three domains is not clear. In this study, we sought to assess the interrelation between social cognition, social functioning, and the expressiveness and experiential factors of negative symptoms in first-episode psychosis (FEP).

SAMPLE AND METHODS

216 patients, participants in a multicentre study (AGES-CM), comprised our study sample. The WHO Disability Assessment Schedule (WHODAS 2.0) was used to assess functioning, whereas the Positive and Negative Schizophrenia Syndrome Scale (PANSS) was used to measure the severity of negative symptoms, and the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) was applied to assess the emotional processing component of social cognition. Network analyses were conducted with the aim of analysing the patterns of relationships between social cognition, social functioning, and the expressiveness and experiential factors of negative symptoms.

RESULTS

Our findings suggest that there is a direct relationship between social cognition and social functioning (weight = -.077), but also an indirect connection between them, mediated by the experiential (but not the expressiveness) factor of negative symptoms (weight = 0.300).

DISCUSSION

The importance of the affectation of subdomains of social cognition, as well as the role of negative symptoms, specifically the experiential factor, in the functioning of patients with FEP seems to be relevant. The inclusion of these factors in prevention and treatment programs would thus allow us to reduce their impact on the social functioning of these patients.

Effects of bilateral, bipolar-nonbalanced, frontal transcranial Direct Current Stimulation (tDCS) on negative symptoms and neurocognition in a sample of patients living with schizophrenia: Results of a randomized double-blind sham-controlled trial

Negative symptoms (NS), conceived as Avolition-Apathy (AA) and Expressive Deficit (EXP) domains, and neurocognitive impairments represent unmet therapeutic needs for patients with schizophrenia. The present study investigated if bilateral bipolar-nonbalanced frontal transcranial Direct Current Stimulation (tDCS) could improve these psychopathological dimensions. This randomized, double-blind, sham-controlled study (active-tDCS versus sham-tDCS, both, n = 25) included 50 outpatients diagnosed with schizophrenia clinically stabilized. Patients received 20-min 2 mA active-tDCS or sham-tDCS (anode: left Dorsolateral Prefrontal Cortex; cathode: right orbitofrontal region). Primary outcomes included: PANSS-Negative subscale, Negative Factor (Neg-PANSS), AA and EXP domains; neurocognitive performance at Brief Assessment of Cognition in Schizophrenia. Secondary outcomes included: PANSS subscales and total score, Disorganized/Concrete (DiscC-PANSS) and Positive Factors, Clinical Global Impression (CGI) scores, clinical insight at Scale to Assess Unawareness of Mental Disorder (SUMD). Analysis of covariance (ANCOVA) was performed evaluating between-group changes over time. Significant improvements following active-tDCS were observed for all NS measures (all, p < 0.001; d > 0.8) and for working memory (p = 0.025, d = 0.31). Greater variations following to active treatment emerged also for PANSS-General Psychopathology subscale (p < 0.001; d = 0.54), PANSS total score (p < 0.001; d = 0.69), CGI indexes (all, p < 0.001; d > 0.6), DiscC-PANSS (p < 0.001; d = 0.80) and SUMD-general Unawareness index (p = 0.005; d = 0.15) but not for positive symptoms and others insight measures. Good safety/tolerability profiles were found. Bilateral bipolar-nonbalanced frontal-tDCS is a non-pharmacological approach in schizophrenia effectively improving NS, particularly the AA and EXP domains, probably acting by modulating dysfunctional cortical-subcortical networks. Preliminary results also suggest working memory improvements following tDCS. Further studies are needed to confirm the neurobiological basis of these results.

The effect of salience of rewards on effort-based decision making in psychotic disorders

BACKGROUND

Although motivational negative symptoms account for reduced functioning and quality of life in individuals with psychotic disorders, the underlying mechanisms are yet not fully understood. Neuroimaging studies suggest that an impaired perception of reward cues could result in a lack of incentive value that then leads to a decrease in goal-directed behavior. Therefore, the aim of this study was to test the effect of increasing the salience of reward cues on goal-directed behavior.

METHODS

We recruited a sample of n = 30 participants with a psychotic disorder and at least mild negative symptoms and n = 30 healthy controls. We used the Balloon Effort Task, an effort-based decision-making paradigm, to assess amotivation on a behavioral level. We manipulated the salience of rewards in the paradigm by highlighting the monetary rewards in half of the trials.

RESULTS

Total effort expenditure did not differ between participants with and without psychotic disorders, but participants with psychotic disorders showed a significantly reduced effort allocation to the level of rewards. The salience of rewards manipulation significantly increased effort expenditure both in participants with psychotic disorders and in the healthy controls, but had no impact on effort allocation.

CONCLUSIONS

Increasing the salience of reward cues promotes goal-directed behavior. This opens up new possibilities for interventions addressing amotivation in individuals with negative symptoms by facilitating the perception of reward cues.

Revisiting the latent structure of negative symptoms in schizophrenia: Evidence from two second-generation clinical assessments

BACKGROUND

Negative symptoms are core symptom of schizophrenia, and many previous research studied the latent structure of negative symptoms based on a single measurement scale. Applying two second-generation negative symptom scales to the same sample can address measurement-invariance of latent structure.

METHODS

Three-hundred-and-five schizophrenia patients were assessed using the CAINS and the BNSS. Confirmatory Factor Analysis (CFA) tested four competing factor-models: (1) a 1-factor model; (2) a 2-factor model comprising the motivation and pleasure (MAP) domain and the diminished expression (EXP) domain; (3) a 5-factor model comprising anhedonia, avolition, asociality, blunted affect and alogia; (4) a hierarchical model comprising the "first-order" 5-domain factors and the "second-order" MAP &amp; EXP factors.

RESULTS

The CFA results for the data of the CAINS showed that the 2-factor model had the best data fit over the other competing models. The CFA using the BNSS data in the same sample also supported the superiority of the 2-factor model. Lastly, after combining the items of the BNSS and CAINS together in the same sample for CFA, the 2-factor model prevailed over the other competing models.

CONCLUSIONS

The 2-factor model appears to be measurement-invariant latent structure of negative symptoms. The novel method of combining the items of the CAINS and BNSS might have circumvented the possible imperfect construct of a single scale. Our findings support the MAP and EXP factors as the latent structure for negative symptoms.

Identifying clinical and psychological correlates of persistent negative symptoms in early-onset psychotic disorders

Persistent negative symptoms (PNS) contribute to impairment in psychosis. The characteristics of PNS seen in youth remained under-investigated. We aimed to demonstrate clinical, treatment-related, and psychosocial characteristics of PNS in early-onset schizophrenia-spectrum disorders (EOSD). 132 patients with EOSD were assessed with Positive and Negative Symptom Scale, Brief Negative Symptom Scale, Calgary Depression Scale for Schizophrenia, and Simpson-Angus Scale. Parenting skills and resilience were evaluated using Parental Attitude Research Instrument and Child and Youth Resilience Measure-12. Longer duration of untreated psychosis (DUP) and prodromal phase were found in primary and secondary PNS groups, compared to the non-PNS group. The primary PNS group was characterized by earlier age-onset, lower smoking rates, and more common clozapine use. Resilience and egalitarian/democratic parenting were negatively correlated with symptoms related to motivation/pleasure and blunted expression. More blunted expression-related symptoms and longer DUP in the first episode significantly predicted primary/secondary PNS at follow-up. Using the data from total negative symptom scores and DUP, Receiver Operating Characteristic analyses significantly differentiated primary/secondary PNS groups from the non-PNS counterparts. PNS associated with blunted expression and low motivation/pleasure in the first episode could persist into clinical follow-up. Effective pharmacological treatment and psychosocial interventions are needed in youth.

Pleasant and unpleasant odor identification ability is associated with distinct dimensions of negative symptoms transdiagnostically in psychotic disorders

Negative symptoms are among the greatest sources of functional impairment for individuals with schizophrenia, yet their mechanisms remain poorly understood. Olfactory impairment is associated with negative symptoms. The processing of pleasant olfactory stimuli is subserved by reward-related neural circuitry while unpleasant olfactory processing is subserved by emotion-related neural circuitry, suggesting that these two odor dimensions may offer a window into differential mechanisms of negative symptoms. We examined whether pleasant and unpleasant odor identification bears differential relationships with avolition and inexpressivity dimensions of negative symptoms, whether these relationships are transdiagnostic, and whether pleasant and unpleasant odor processing also relate differently to other domains of functioning in a sample of individuals diagnosed with schizophrenia (N = 54), other psychotic disorders (N = 65), and never-psychotic adults (N = 160). Hierarchical regressions showed that pleasant odor identification was uniquely associated with avolition, while unpleasant odor identification was uniquely associated with inexpressivity. These relationships were largely transdiagnostic across groups. Additionally, pleasant and unpleasant odor identification displayed signs of specificity with other functional and cognitive measures. These results align with past work suggesting dissociable pathomechanisms of negative symptoms and provide a potential avenue for future work using valence-specific olfactory dysfunction as a semi-objective and low-cost marker for understanding and predicting the severity of specific negative symptom profiles.

The Important Role of Motivation and Pleasure Deficits on Social Functioning in Patients With Schizophrenia: A Network Analysis

Negative symptoms, particularly the motivation and pleasure (MAP) deficits, are associated with impaired social functioning in patients with schizophrenia (SCZ). However, previous studies seldom examined the role of the MAP on social functioning while accounting for the complex interplay between other psychopathology. This network analysis study examined the network structure and interrelationship between negative symptoms (at the "symptom-dimension" and "symptom-item" levels), other psychopathology and social functioning in a sample of 269 patients with SCZ. The psychopathological symptoms were assessed using the Clinical Assessment Interview for Negative Symptoms (CAINS) and the Positive and Negative Syndrome Scale (PANSS). Social functioning was evaluated using the Social and Occupational Functioning Assessment Scale (SOFAS). Centrality indices and relative importance of each node were estimated. The network structures between male and female participants were compared. Our resultant networks at both the "symptom-dimension" and the "symptom-item" levels suggested that the MAP factor/its individual items were closely related to social functioning in SCZ patients, after controlling for the complex interplay between other nodes. Relative importance analysis showed that MAP factor accounted for the largest proportion of variance of social functioning. This study is among the few which used network analysis and the CAINS to examine the interrelationship between negative symptoms and social functioning. Our findings supported the pivotal role of the MAP factor to determine SCZ patients' social functioning, and as a potential intervention target for improving functional outcomes of SCZ.

Longitudinal invariance of the positive and negative syndrome scale negative dimension in antipsychotic naïve first-episode schizophrenia

AIM

Construct stability over time is required for reliable inference, but evidence regarding the longitudinal invariance of negative symptoms is still limited. Thus, we examined the longitudinal invariance of the negative dimension using the positive and negative syndrome scale (PANSS) in an antipsychotic-naïve first-episode schizophrenia sample at baseline and after 10 weeks.

METHODS

Our study was conducted at a specialized early intervention service. PANSS ratings were analysed for 138 patients, and two different models were specified and tested: a unidimensional and a two-correlated factor solution.

RESULTS

The unidimensional model fulfilled criteria for longitudinal invariance, whilst the two-correlated did not.

CONCLUSION

Our study provides support for the PANSS negative unidimensional model use to evaluate negative symptoms' longitudinal change following first-episode schizophrenia.

Does effort-cost decision-making relate to real-world motivation in people living with HIV?

INTRODUCTION

Low motivation is frequent in older people with HIV, yet poorly understood. Effort-cost decision-making (ECDM) tasks inspired by behavioral economics have shown promise as indicators of motivation or apathy. These tasks assess the willingness to exert effort to earn a monetary reward, providing an estimate of the subjective "cost" of effort for each participant. Here we sought evidence for a relationship between ECDM task performance and self-reported motivation in a cross-sectional study involving 80 middle-aged and older people with well-controlled HIV infection, a chronic health condition with a high burden of mental and cognitive health challenges.

METHODS

Participants attending a regular follow-up visit for a Canadian longitudinal study of brain health in HIV completed a computerized ECDM task and a self-report measure of motivation. Other brain health measures were available, collected for the parent study (cognition, depression, anxiety, and vitality, as well as self-reported time spent on real-world leisure activities).

RESULTS

Contrary to our hypothesis, we found no relationship between ECDM performance and self-reported motivation. However, those willing to accept higher effort in the ECDM task also reported more time engaged in real-world activities. This association had a small-to-moderate effect size.

CONCLUSIONS

The behavioral economics construct of subjective cost of effort, measured with a laboratory ECDM task, does not relate to motivation in people living with chronic HIV. However, the task shows some relationship with real-world goal-directed behavior, suggesting this construct has potential clinical relevance. More work is needed to understand how the subjective cost of effort plays out in clinical symptoms and everyday activities.

Psychological Dimensions Relevant to Motivation and Pleasure in Schizophrenia

Motivation and pleasure deficits are common in schizophrenia, strongly linked with poorer functioning, and may reflect underlying alterations in brain functions governing reward processing and goal pursuit. While there is extensive research examining cognitive and reward mechanisms related to these deficits in schizophrenia, less attention has been paid to psychological characteristics that contribute to resilience against, or risk for, motivation and pleasure impairment. For example, psychological tendencies involving positive future expectancies (e.g., optimism) and effective affect management (e.g., reappraisal, mindfulness) are associated with aspects of reward anticipation and evaluation that optimally guide goal-directed behavior. Conversely, maladaptive thinking patterns (e.g., defeatist performance beliefs, asocial beliefs) and tendencies that amplify negative cognitions (e.g., rumination), may divert cognitive resources away from goal pursuit or reduce willingness to exert effort. Additionally, aspects of sociality, including the propensity to experience social connection as positive reinforcement may be particularly relevant for pursuing social goals. In the current review, we discuss the roles of several psychological characteristics with respect to motivation and pleasure in schizophrenia. We argue that individual variation in these psychological dimensions is relevant to the study of motivation and reward processing in schizophrenia, including interactions between these psychological dimensions and more well-characterized cognitive and reward processing contributors to motivation. We close by emphasizing the value of considering a broad set of modulating factors when studying motivation and pleasure functions in schizophrenia.

Affective Dysregulation Precedes Emergence of Psychosis-Like Experiences in a Community Sample of Young Adults

Affective dysregulation (AD) among persons with schizophrenia spectrum disorders, involving the tendency to exhibit sensitivity to minor stress and negative affective states, is an important diagnostic feature and relates to poorer functional and clinical outcomes. Studies of persons with elevated risk for psychosis demonstrate similar AD to those with schizophrenia, and literature suggest a potential influence of AD in the transition from psychosis-like symptoms (PLEs) to disorder. Cross-sectional investigations to date have supported the link between AD and psychosis, and longitudinal studies have mostly yielded mixed findings without demonstration of potential causal relationships between AD and psychosis. This study examined the concurrent and predictive relationships between AD and PLE in a community sample of youth (n = 630) with attention to distinct facets of AD as a latent construct, including low resiliency, low reactive control, and negative emotionality, using structural equation to estimate a longitudinal cross-lagged and autoregressive model across 3 study waves from 15 to 24 years of age. As hypothesized, AD in the mid-teen years predicted subsequent PLE 3 years later. In addition, we found that increasing PLE in the end of the teen years related to a subsequent increase in AD in the early 20s. A cross-sectional relationship between AD and PLE in the mid-teen years was also supported. Findings overall describe important relationships between AD and PLE that appear to vary with developmental stage, implicating various factors to inform approaches for identifying youth who may be at risk for subsequent PLE or other mental health conditions.

Impact of Negative Symptoms on Functioning and Quality of Life in First Psychotic Episodes of Schizophrenia

Negative symptoms are not considered a unitary construct encompassing two different domains, diminished expression, and avolition-apathy. The aim of this study was to explore the relationships between each domain and psychosocial functioning and quality of life in people with a first psychotic episode of schizophrenia. In total, 61 outpatients were assessed with the Clinical Assessment Interview for Negative Symptoms (CAINS), The Functioning Assesment Short Test (FAST) and The Quality of Life Scale (QLS). The mean global score for CAINS was 21.5 (SD: 15.6), with a CAINS Avolition-Apathy (MAP) score of 17.0 (SD: 11.8), and CAINS Diminished Expression (EXP) score of 4.5 (SD: 5.0). The mean FAST score was 31.9 (SD: 18.9), and 41.1 (SD: 17.9) for QLS. Linear regression analysis revealed a significant (F(4,53) = 15.65, p < 0.001) relationship between MAP and EXP CAINS’ score and FAST score. CAINS-MAP was more predictive of FAST scores (β = 0.44, p = 0.001) than CAINS-EXP (β = 0.37, p = 0.007). Linear regression analysis for QLS revealed a significant model (F(4,56) = 29.29, p < 0.001). The standardized regression weight for the CAINS-MAP was around three times greater (β = −0.63, p < 0.001) than for CAINS-EXP (β = −0.24, p = 0.024). The two different domains are associated differently with functionality and quality of life.

Psychological adjustment following mechanical restraint in individuals with schizophrenia

AIM

While it is known that being mechanically restrained during hospitalization can, in severe cases, lead to PTSD in individuals with mental illness, less is known about why some develop posttraumatic stress reactions following restraint while others do not. This study examined whether the amount of exposure to mechanical restraint and patients' interpretations of the episodes' centrality to their identity were related to symptoms of PTSD in individuals with schizophrenia.

METHODS

We asked 20 individuals to recall mechanical restraint episodes and rate them on centrality to identity. They also completed scales measuring symptoms of posttraumatic stress, depression, trauma history, and were rated on positive and negative symptoms. Objective information about the number of times they had been restrained was obtained through Danish health registries.

RESULTS

Amount of exposure to mechanical restraint was not significantly related to PTSD symptoms, potentially due to limitations of our small sample. However, interpreting episodes as more central to identity was. This relationship remained significant when controlling for trauma history, positive symptoms, and depression.

CONCLUSION

The results suggest that clinically significant levels of PTSD are common in this population, and that considering patients' subjective interpretations of restraint episodes, and not merely the objective facts surrounding them is important for patients' psychological adjustment.

Two Factors, Five Factors, or Both? External Validation Studies of Negative Symptom Dimensions in Schizophrenia

OBJECTIVES

Negative symptom studies frequently use single composite scores as indicators of symptom severity and as primary endpoints in clinical trials. Factor analytic and external validation studies do not support this practice but rather suggest a multidimensional construct. The current study used structural equation modeling (SEM) to compare competing dimensional models of negative symptoms to determine the number of latent dimensions that best capture variance in biological, psychological, and clinical variables known to have associations with negative symptoms.

METHODS

Three independent studies (total n = 632) compared unidimensional, two-factor, five-factor, and hierarchical conceptualizations of negative symptoms in relation to cognition, psychopathology, and community functioning (Study 1); trait emotional experience and defeatist performance beliefs (Study 2); and glutamate and gamma-aminobutyric acid levels in the anterior cingulate cortex quantified using proton magnetic resonance spectroscopy (Study 3).

RESULTS

SEM favored the five-factor and hierarchical models over the unidimensional and two-factor models regardless of the negative symptom measure or external validator. The five dimensions-anhedonia, asociality, avolition, blunted affect, and alogia-proved vital either as stand-alone domains or as first-order domains influenced by second-order dimensions-motivation and pleasure and emotional expression. The two broader dimensions sometimes masked important associations unique to the five narrower domains. Avolition, anhedonia, and blunted affect showed the most domain-specific associations with external variables across study samples.

CONCLUSIONS

Five domains and a hierarchical model reflect the optimal conceptualization of negative symptoms in relation to external variables. Clinical trials should consider using the two dimensions as primary endpoints and the five domains as secondary endpoints.

Validation of the French Clinical Assessment Interview for Negative Symptoms in a Sample of Stable French Individuals With Schizophrenia

OBJECTIVES

The Clinical Assessment Interview for Negative Symptoms (CAINS) is an interview-based instrument evaluating the existence and severity of negative symptoms in people diagnosed with schizophrenia or schizoaffective disorder. The aim of this study is to translate and validate a French version of the CAINS in a French sample of outpatients diagnosed with schizophrenia or schizoaffective disorder.

METHODS

In this study, we included 84 outpatients with a diagnosis of schizophrenia from the University Department of Adult Psychiatry in Montpellier, France. All participants were assessed for the severity of negative symptoms as well as level of depression. Psychometric properties of the French CAINS were investigated including its factor structure, internal consistency, and interrater and test-retest reliabilities. We also determined the discriminant and convergent validity.

RESULTS

Exploratory factor analysis and parallel analysis reproduced the two-factor model, and explained 43.55% of the total score variation with good internal consistency (Cronbach α of 0.87). Both interrater and test-retest reliabilities were high for the CAINS and its subscales (intraclass correlation coefficient range, 0.89-0.99). The standard errors of measurement and minimal detectable change were also investigated. Convergent validity of the CAINS was underpinned by correlations obtained with various measures of negative symptoms. Adequate discriminant validity was established by showing that the CAINS did not correlate with positive symptoms.

CONCLUSION

Overall, our results obtained were similar to those found in the original study of the CAINS. Structural analyses also replicated the two-factor model of the CAINS. Our results indicate that the French CAINS has robust psychometric properties and is a valid tool for evaluating negative symptoms in French-speaking individuals diagnosed with schizophrenia.

Aberrant striatal coupling with default mode and central executive network relates to self-reported avolition and anhedonia in schizophrenia

BACKGROUND

Avolition and anhedonia are common symptoms in schizophrenia and are related to poor long-term prognosis. There is evidence for aberrant cortico-striatal function and connectivity as neural substrate of avolition and anhedonia. However, it remains unclear how both relate to shared or distinct striatal coupling with large-scale intrinsic networks. Using resting state functional magnetic resonance imaging (rs-fMRI) this study investigated the association of large-scale cortico-striatal functional connectivity with self-reported and clinician-rated avolition and anhedonia in subjects with schizophrenia.

METHODS

Seventeen subjects with schizophrenia (SZ) and 28 healthy controls (HC) underwent rs-fMRI. Using Independent Component Analysis (ICA), we assessed Independent Components (ICs) reflecting intrinsic connectivity networks (ICNs), intra intrinsic functional connectivity within the ICs (intra-iFC), and intrinsic functional connectivity between different ICs (inter-iFC). Avolition and anhedonia were assessed using the Self Evaluation Scale for Negative Symptoms and the Brief Negative Symptom Scale.

RESULTS

ICA revealed three striatal components and six cortical ICNs. Both self-rated avolition and anhedonia correlated with increased inter-iFC between the caudate and posterior Default Mode Network (pDMN) and between the caudate and Central Executive Network (CEN). In contrast, clinician-rated avolition and anhedonia were not correlated with cortico-striatal connectivity. Group comparison revealed trend-wise decreased inter-iFC between the caudate and Salience Network (SN) in schizophrenia patients compared to HC.

DISCUSSION

Self-rated, but not clinician-rated, avolition and anhedonia was associated with aberrant striatal coupling with the default mode and the central executive network. These findings suggest that self-reported and clinician-rated scores might capture different aspects of motivational and hedonic deficits in schizophrenia and therefore relate to different cortico-striatal functional abnormalities.

Negative symptoms in alcohol use disorder: A pilot study applying the two-factor model of negative symptoms to patients with alcohol use disorder

BACKGROUND AND AIMS

Alcohol Use Disorder (AUD) is characterized by a reduction in goal-directed behavior, with alcohol use taking precedence over other areas of life. These features in AUD resemble negative symptoms in schizophrenia, especially the reduction in motivation and pleasure (MAP). Given the clinical similarities of negative symptoms across diagnostic categories, it comes as a surprise that there are few investigations on negative symptoms in alcohol and other substance use disorders. To our knowledge, our study is the first to assess negative symptoms in AUD based on a two-factorial approach, and to investigate the interrelation of these dimensions with the severity of AUD, and alcohol craving.

MATERIALS AND METHODS

We examined a sample of 42 patients with AUD at the Psychiatric University Hospital in Zurich. Participants provided self-report and interview-based measures of the severity of AUD, negative symptoms, and alcohol craving. Finally, we used data from the electronic health records of the patients.

RESULTS

Patients with AUD show negative symptoms to a similar extent as patients with schizophrenia or bipolar disorder. We found a positive correlation between the extent of impairment within the MAP factor and overall severity of AUD. Furthermore, MAP negative symptoms were correlated with alcohol craving. In a linear regression, negative symptoms predicted alcohol craving whereas depression did not.

SUMMARY

Negative symptoms as conceptualized for schizophrenia are prevalent in patients with AUD and associated with the severity of AUD. More specifically, severity of AUD correlates with diminished motivation and pleasure, highlighting the importance of disturbances in motivational functions in AUD. This is further supported by the correlation between negative symptoms and craving, a hallmark of AUD. Taken together, our findings suggest that negative symptoms might be a highly relevant but hitherto often neglected therapeutic target in AUD.

New and emerging treatments for schizophrenia: a narrative review of their pharmacology, efficacy and side effect profile relative to established antipsychotics

Schizophrenia is associated with substantial unmet needs, highlighting the necessity for new treatments. This narrative review compares the pharmacology, clinical trial data and tolerability of novel medications to representative antipsychotics. Cariprazine, brexpiprazole and brilaroxazine are partial dopamine agonists effective in acute relapse. Lumateperone (serotonin and dopamine receptor antagonist) additionally benefits asocial and depressive symptoms. F17464 (D3 antagonist and 5-HT1A partial agonist) has one positive phase II study. Lu AF35700 (dopamine and serotonin receptor antagonist) was tested in treatment-resistance with no positive results. Pimavanserin, roluperidone, ulotaront and xanomeline do not act directly on the D2 receptor at clinical doses. Initial studies indicate pimavanserin and roluperidone improve negative symptoms. Ulotaront and xanomeline showed efficacy for positive and negative symptoms of schizophrenia in phase II trials. BI 409306, BI 425809 and MK-8189 target glutamatergic dysfunction in schizophrenia, though of these only BI 425809 showed efficacy. These medications largely have favourable cardiometabolic side-effect profiles. Overall, the novel pharmacology, clinical trial and tolerability data indicate these compounds are promising new additions to the therapeutic arsenal.