Long-term cognitive trajectories and heterogeneity in patients with schizophrenia and their unaffected siblings

Moving from supported to independent living: what are the barriers and facilitators for individuals with psychosis?

PURPOSE

Living independently, as opposed to in sheltered housing or with caregivers, is an important aim in the recovery of individuals with psychosis, but the transition to independence can be challenging. This study aims to investigate how individuals with psychosis move between living arrangements and to identify the barriers and facilitators of moving towards independence.

METHODS

The living arrangements of 1119 individuals with non-affective psychosis from the Genetic Risk and Outcome of Psychosis study were assessed at baseline, at three- and six-year follow-ups and further categorized as either supported (sheltered housing or with parents) or independent (single or with partner/family). We estimated the probabilities of transitioning between the living statuses and investigated the influence of demographic characteristics, symptomatology, cognition, social support, and premorbid social adjustment on transition using Markov chain modelling.

RESULTS

The majority of individuals living in supported housing remained there during the six-year follow-up period (~ 60%). The likelihood of moving from supported to independent living was twice as high for participants who were younger, five-to-six times higher for women, twice as high for individuals with better overall cognition, and five times higher for those with a course of low positive symptoms.

CONCLUSION

This study highlights that a large group of individuals with psychosis in supported housing is unlikely to move to independent living. Older men with cognitive impairments and who show continuous severe positive symptoms are the least likely to move living independently. Tailored interventions for these at-risk individuals could increase their chances of moving to independent living.

Association of clinical symptoms and cardiometabolic dysregulations in patients with schizophrenia spectrum disorders

BACKGROUND

Patients with schizophrenia spectrum disorders (SSD) have a shortened life expectancy related to cardiovascular diseases. We investigated the association of cognitive, positive, and negative symptoms with cardiometabolic dysregulations in SSD patients.

METHODS

Overall, 1,119 patients from the Genetic Risk and Outcome in Psychosis (GROUP) study were included. Cognitive function, positive and negative symptoms were assessed at baseline, 3-year, and 6-year. Cardiometabolic biomarkers were measured at 3-year follow-up. We used linear and multinomial logistic regression models to test the association between cardiometabolic biomarkers and clinical trajectories and performed mediation analyzes, while adjusting for clinical and demographic confounders.

RESULTS

Cognitive performance was inversely associated with increased body mass index (mean difference [β], βhigh = -1.24, 95% CI = -2.28 to 0.20, P = 0.02) and systolic blood pressure (βmild = 2.74, 95% CI = 0.11 to 5.37, P = 0.04). The severity of positive symptoms was associated with increased glycated hemoglobin (HbA1c) levels (βlow = -2.01, 95% CI = -3.21 to -0.82, P = 0.001). Increased diastolic blood pressure (ORhigh-decreased = 1.04, 95% CI = 1.01 to 1.08, P = 0.02; ORhigh-increased = 1.04, 95% CI = 1.00 to 1.08, P = 0.048) and decreased high-density lipoprotein (OR high-increased = 6.25, 95% CI = 1.81 to 21.59, P = 0.004) were associated with more severe negative symptoms. Increased HbA1c (ORmoderate = 1.05, 95% CI = 1.01 to 1.10, P = 0.024; ORhigh = 1.08, 95% CI = 1.02 to 1.14, P = 0.006) was associated with more severe positive symptoms. These associations were not mediated by antipsychotics.

CONCLUSIONS

We showed an association between cardiometabolic dysregulations and clinical and cognitive symptoms in SSD patients. The observed associations underscore the need for early identification of patients at risk of cardiometabolic outcomes.

Understanding Lifelong Factors and Prediction Models of Social Functioning After Psychosis Onset Using the Large-Scale GROUP Cohort Study

BACKGROUND AND HYPOTHESIS

Current rates of poor social functioning (SF) in people with psychosis history reach 80% worldwide. We aimed to identify a core set of lifelong predictors and build prediction models of SF after psychosis onset.

STUDY DESIGN

We utilized data of 1119 patients from the Genetic Risk and Outcome in Psychosis (GROUP) longitudinal Dutch cohort. First, we applied group-based trajectory modeling to identify premorbid adjustment trajectories. We further investigated the association between the premorbid adjustment trajectories, six-year-long cognitive deficits, positive, and negative symptoms trajectories, and SF at 3-year and 6-year follow-ups. Next, we checked associations between demographics, clinical, and environmental factors measured at the baseline and SF at follow-up. Finally, we built and internally validated 2 predictive models of SF.

STUDY RESULTS

We found all trajectories were significantly associated with SF (P < .01), explaining up to 16% of SF variation (R2 0.15 for 3- and 0.16 for 6-year follow-up). Demographics (sex, ethnicity, age, education), clinical parameters (genetic predisposition, illness duration, psychotic episodes, cannabis use), and environment (childhood trauma, number of moves, marriage, employment, urbanicity, unmet needs of social support) were also significantly associated with SF. After validation, final prediction models explained a variance up to 27% (95% CI: 0.23, 0.30) at 3-year and 26% (95% CI: 0.22, 0.31) at 6-year follow-up.

CONCLUSIONS

We found a core set of lifelong predictors of SF. Yet, the performance of our prediction models was moderate.

Deep Clinical Phenotyping of Schizophrenia Spectrum Disorders Using Data-Driven Methods: Marching towards Precision Psychiatry

Heterogeneity is the main challenge in the traditional classification of mental disorders, including schizophrenia spectrum disorders (SSD). This can be partly attributed to the absence of objective diagnostic criteria and the multidimensional nature of symptoms and their associated factors. This article provides an overview of findings from the Genetic Risk and Outcome of Psychosis (GROUP) cohort study on the deep clinical phenotyping of schizophrenia spectrum disorders targeting positive and negative symptoms, cognitive impairments and psychosocial functioning. Three to four latent subtypes of positive and negative symptoms were identified in patients, siblings and controls, whereas four to six latent cognitive subtypes were identified. Five latent subtypes of psychosocial function-multidimensional social inclusion and premorbid adjustment-were also identified in patients. We discovered that the identified subtypes had mixed profiles and exhibited stable, deteriorating, relapsing and ameliorating longitudinal courses over time. Baseline positive and negative symptoms, premorbid adjustment, psychotic-like experiences, health-related quality of life and PRS_SCZ were found to be the strong predictors of the identified subtypes. Our findings are comprehensive, novel and of clinical interest for precisely identifying high-risk population groups, patients with good or poor disease prognosis and the selection of optimal intervention, ultimately fostering precision psychiatry by tackling diagnostic and treatment selection challenges pertaining to heterogeneity.

A new era for schizophrenia drug development - Lessons for the future

For many patients and their treating clinicians, the pharmacological management of psychotic symptoms centres on trying to find a regime that balances efficacy and quality of life, impairing side effects associated with dopamine antagonism. Recent reports of a positive Phase III study from Karuna Therapeutics indicate that the first primarily non-dopamine-based treatment for schizophrenia may come to market soon with the potential for substantially reduced or differentiated side effects. Against a background of repeated failures, Karuna's success promises a desperately needed new treatment option for patients. It also reflects some hard-won lessons about the methodology for schizophrenia drug development. Teaser A positive Phase II study and positive media report from a Phase III study with xanomeline/trospium may herald the first truly new treatment option for schizophrenia patients in decades. This drug's journey to this point reflects some hard-won lessons about the methodology for schizophrenia drug development.

Cognitive impairment in schizophrenia: aetiology, pathophysiology, and treatment

Cognitive deficits are a core feature of schizophrenia, account for much of the impaired functioning associated with the disorder and are not responsive to existing treatments. In this review, we first describe the clinical presentation and natural history of these deficits. We then consider aetiological factors, highlighting how a range of similar genetic and environmental factors are associated with both cognitive function and schizophrenia. We then review the pathophysiological mechanisms thought to underlie cognitive symptoms, including the role of dopamine, cholinergic signalling and the balance between GABAergic interneurons and glutamatergic pyramidal cells. Finally, we review the clinical management of cognitive impairments and candidate novel treatments.

MICEmi: A method to identify cognitive endophenotypes of mental illnesses

BACKGROUND

Characterizing neurocognitive endophenotypes of mental illnesses (MIs) could be useful for identifying at-risk individuals, increasing early diagnosis, improving disease subtyping, and proposing therapeutic strategies to reduce the negative effects of the symptoms, in addition to serving as a scientific basis to unravel the physiopathology of the disease. However, a standardized algorithm to determine cognitive endophenotypes has not yet been developed. The main objective of this study was to present a method for the identification of endophenotypes in MI research.

METHODS

For this purpose, a 14-expert working group used a scoping review methodology and designed a method that includes a scoring template with five criteria and indicators, a strategy for their verification, and a decision tree.

CONCLUSIONS

This work is ongoing since it is necessary to obtain external validation of the applicability of the method in future research.

A subtype of institutionalized patients with schizophrenia characterized by pronounced subcortical and cognitive deficits

Some patients with schizophrenia have severe cognitive impairment and functional deficits that require long-term institutional care. The patterns of brain-behavior alterations in these individuals, and their differences from patients living successfully in the community, remain poorly understood. Previous cognition-based studies for stratifying schizophrenia patients highlight the importance of subcortical structures in the context of illness heterogeneity. In the present study, subcortical volumes from 96 institutionalized patients with long-term schizophrenia were evaluated using cluster analysis to test for heterogeneity. These data were compared to those from two groups of community-dwelling individuals with schizophrenia for comparison purposes, including 68 long-term ill and 126 first-episode individuals. A total of 290 demographically matched healthy participants were included as normative references at a 1:1 ratio for each patient sample. A subtype of institutionalized patients was identified based on their pattern of subcortical alterations. Using a machine learning algorithm developed to discriminate the two groups of institutionalized patients, all three patient samples were found to have similar rates of patients assigned to the two subtypes (approximately 50% each). In institutionalized patients, only the subtype with the identified pattern of subcortical alterations had greater neocortical and cognitive abnormalities than those in the similarity classified community-dwelling patients with long-term illness. Thus, for the subtype of patients with a distinctive pattern of subcortical alterations, when the distinct pattern of subcortical alterations is present and particularly severe, it is associated with cognitive impairments that may contribute to persistent disability and institutionalization.

Effects of socioeconomic status in cognition of people with schizophrenia: results from a Latin American collaboration network with 1175 subjects

BACKGROUND

Cognition heavily relies on social determinants and genetic background. Latin America comprises approximately 8% of the global population and faces unique challenges, many derived from specific demographic and socioeconomic variables, such as violence and inequality. While such factors have been described to influence mental health outcomes, no large-scale studies with Latin American population have been carried out. Therefore, we aim to describe the cognitive performance of a representative sample of Latin American individuals with schizophrenia and its relationship to clinical factors. Additionally, we aim to investigate how socioeconomic status (SES) relates to cognitive performance in patients and controls.

METHODS

We included 1175 participants from five Latin American countries (Argentina, Brazil, Chile, Colombia, and Mexico): 864 individuals with schizophrenia and 311 unaffected subjects. All participants were part of projects that included cognitive evaluation with MATRICS Consensus Cognitive Battery and clinical assessments.

RESULTS

Patients showed worse cognitive performance than controls across all domains. Age and diagnosis were independent predictors, indicating similar trajectories of cognitive aging for both patients and controls. The SES factors of education, parental education, and income were more related to cognition in patients than in controls. Cognition was also influenced by symptomatology.

CONCLUSIONS

Patients did not show evidence of accelerated cognitive aging; however, they were most impacted by a lower SES suggestive of deprived environment than controls. These findings highlight the vulnerability of cognitive capacity in individuals with psychosis in face of demographic and socioeconomic factors in low- and middle-income countries.

Lifespan evolution of neurocognitive impairment in schizophrenia - A narrative review

Cognitive impairment is a well-recognized key feature of schizophrenia. Here we review the evidence on (1) the onset and sensitive periods of change in cognitive impairment before and after the first psychotic episode, and (2) heterogeneity in neurocognitive presentations across cognitive domains between and within individuals. Overall, studies suggest that mild cognitive impairment in individuals who develop schizophrenia or related disorders is already present during early childhood. Cross-sectional studies further suggest increasing cognitive impairments from pre- to post-psychosis onset, with the greatest declines between adolescence, the prodrome, and the first psychotic episode and with some variability between domains. Longitudinal studies with more than 10 years of observation time are scarce but support mild cognitive declines after psychosis onset until late adulthood. Whether and how much this cognitive decline exceeds normal aging, proceeds further in older patients, and is specific to certain cognitive domains and subpopulations of patients remains to be investigated. Finally, studies show substantial heterogeneity in cognitive performance in schizophrenia and suggest a variety of impairment profiles.

This review highlights a clear need for long-term studies that include a control group and individuals from adolescence to old age to better understand critical windows of cognitive change and their predictors. The available evidence stresses the importance of interventions that aim to counter cognitive decline during the prodromal years, as well as careful assessment of cognition in order to determine who will profit most from which cognitive training.

Investigating data-driven biological subtypes of psychiatric disorders using specification-curve analysis

BACKGROUND

Cluster analyses have become popular tools for data-driven classification in biological psychiatric research. However, these analyses are known to be sensitive to the chosen methods and/or modelling options, which may hamper generalizability and replicability of findings. To gain more insight into this problem, we used Specification-Curve Analysis (SCA) to investigate the influence of methodological variation on biomarker-based cluster-analysis results.

METHODS

Proteomics data (31 biomarkers) were used from patients (n = 688) and healthy controls (n = 426) in the Netherlands Study of Depression and Anxiety. In SCAs, consistency of results was evaluated across 1200 k-means and hierarchical clustering analyses, each with a unique combination of the clustering algorithm, fit-index, and distance metric. Next, SCAs were run in simulated datasets with varying cluster numbers and noise/outlier levels to evaluate the effect of data properties on SCA outcomes.

RESULTS

The real data SCA showed no robust patterns of biological clustering in either the MDD or a combined MDD/healthy dataset. The simulation results showed that the correct number of clusters could be identified quite consistently across the 1200 model specifications, but that correct cluster identification became harder when the number of clusters and noise levels increased.

CONCLUSION

SCA can provide useful insights into the presence of clusters in biomarker data. However, SCA is likely to show inconsistent results in real-world biomarker datasets that are complex and contain considerable levels of noise. Here, the number and nature of the observed clusters may depend strongly on the chosen model-specification, precluding conclusions about the existence of biological clusters among psychiatric patients.

Neurocognitive heterogeneity in 7-year-old children at familial high risk of schizophrenia or bipolar disorder: The Danish high risk and resilience study - VIA 7

BACKGROUND

Studies of neurocognitive heterogeneity in young children at familial high-risk of bipolar disorder (FHR-BP) or schizophrenia (FHR-SZ) are important to investigate inter-individual neurocognitive differences. We aimed to identify neurocognitive subgroups, describe prevalence of FHR-BP or FHR-SZ children herein, and examine risk ratios (RR) compared with controls.

METHODS

In a population-based cohort of 514 7-year-old children (197 FHR-SZ, 118 FHR-BP, and 199 matched controls) we used hierarchical cluster analyses to identify subgroups across 14 neurocognitive indices.

RESULTS

Three neurocognitive subgroups were derived: A Mildly Impaired (30%), Typical (51%), and Above Average subgroup (19%). The Mildly Impaired subgroup significantly underperformed controls (Cohen d = 0.11-1.45; Ps < 0.001) except in set-shifting (P = .84). FHR-SZ children were significantly more prevalent in the Mildly Impaired subgroup; FHR-BP children were more so in the Above Average subgroup (X² (2, N = 315) = 9.64, P < .01). 79.7% FHR-BP and 64.6% FHR-SZ children demonstrated typical or above average neurocognitive functions. Neurocognitive heterogeneity related significantly to concurrent functioning, psychopathology severity, home environment adequacy, and polygenic scores for schizophrenia (Ps <. 01). Compared with controls, FHR-SZ and FHR-BP children had a 93% (RR, 1.93; 95% CI, 1.40-2.64) and 8% (RR, 1.08; 95% CI, 0.71-1.66) increased risk of Mildly Impaired subgroup membership.

LIMITATIONS

Limitations include the cross-sectional design and smaller FHR-BP sample size.

CONCLUSIONS

Identification of neurocognitive heterogeneity in preadolescent children at FHR-BP or FHR-SZ may ease stigma and enable pre-emptive interventions to enhance neurocognitive functioning and resilience to mental illness in the impaired sub-population.

Neurocognitive trajectories and their clinical implications in first-episode schizophrenia after one year of antipsychotic treatment

Neurocognitive impairment is a core feature of schizophrenia, and patients with first-episode schizophrenia (FES) are optimal candidates for cognitive remediation, but we do not know enough about the incidence, severity and longitudinal changes in neurocognitive impairment in those with FES. This study aimed to assess the neurocognitive trajectories of patients with FES and to compare the clinical and functional outcomes among those with different trajectories. A total of 562 untreated patients with FES completed a neurocognitive test battery and psychopathological and functional assessment. A total of 373 patients attended the follow-up. Group-based trajectory modelling (GBTM) was applied to identify neurocognitive trajectories. Analysis of variance and chi-square tests were conducted to compare demographic characteristics, multiple neurocognitive domains, and clinical and functional outcomes among the different subgroups. We identified three neurocognitive subgroups: preserved (n = 133), mildly to moderately impaired (n = 187) and severely impaired (n = 53). Neurocognitive function in the two impaired subgroups improved within a year but failed to reach the normal level. The processing speed followed trajectories similar to those of overall cognition. The three subgroups did not significantly differ in antipsychotic usage or clinical remission rate. The severely impaired subgroup had poorer functional outcomes than the preserved subgroup, but the mildly to moderately impaired subgroup did not. Patients with FES followed distinct neurocognitive trajectories during the first year of treatment. Patients with severe neurocognitive impairment have poorer functional outcomes, which require and are more likely to benefit from cognitive remediation. Processing speeding is a potential indicator for screening overall cognition.

OCT and OCT Angiography Offer New Insights and Opportunities in Schizophrenia Research and Treatment

The human retina and retinal imaging technologies continue to increasingly gain the attention of schizophrenia researchers. With the same embryologic origin as the brain, the retina offers a window into neurovascular changes that may underlie disease. Recently, two technologies that have already revolutionized the field of ophthalmology, optical coherence tomography (OCT), and a functional extension of this, optical coherence tomography angiography (OCTA), have gained traction. Together, these non-invasive technologies allow for microscopic imaging of both structural and vascular features of the retina. With ease of use and no side effects, these devices are likely to prove powerful digital health tools in the study and treatment of schizophrenia. They may also prove key to discovering disease relevant biomarkers that underly neurodevelopmental and neurodegenerative aspects of conditions such as schizophrenia.

Association between cognitive phenotype in unaffected siblings and prospective 3- and 6-year clinical outcome in their proband affected by psychosis

BACKGROUND

Cognitive alterations are a central and heterogeneous trait in psychotic disorders, driven by environmental, familial and illness-related factors. In this study, we aimed to prospectively investigate the impact of high familial risk for cognitive alterations, unconfounded by illness-related factors, on symptomatic outcomes in patients.

METHODS

In total, 629 probands with non-affective psychosis and their sibling not affected by psychosis were assessed at baseline, 3- and 6-year follow-up. Familial cognitive risk was modeled by three cognitive subtypes ('normal', 'mixed' and 'impaired') in the unaffected siblings. Generalized linear mixed models assessed multi-cross-sectional associations between the sibling cognitive subtype and repeated measures of proband symptoms across all assessments. Between-group differences over time were assessed by adding an interaction effect of time and sibling cognitive subtype.

RESULTS

Probands affected by psychosis with a sibling of the impaired cognitive subtype were less likely to be in symptomatic remission and showed more disorganization across all time points. When assessing differences over time, probands of siblings with the impaired cognitive subtype showed less remission and less improvement of disorganization after 3 and 6 years relative to the other subtypes. They also showed less reduction of positive, negative and excitement symptoms at 6-year follow-up compared to probands with a sibling of the normal cognitive subtype.

CONCLUSIONS

Cross-sibling pathways from higher levels of familial cognitive vulnerability to worse long-term outcomes may be informative in identifying cognition-related environmental and genetic risks that impact psychotic illness heterogeneity over time.

Accelerated aging signatures in subjects with schizophrenia and their unaffected siblings

Schizophrenia (SZ) is a chronic debilitating disease. Subjects with SZ have significant shorter life expectancy. Growing evidence suggests that a process of pathological accelerated aging occurs in SZ, leading to early development of severe clinical diseases and worse morbimortality. Furthermore, unaffected relatives can share certain endophenotypes with subjects with SZ. We aim to characterize accelerated aging as a possible endophenotype of schizophrenia by using a machine learning (ML) model of peripheral biomarkers to accurately differentiate subjects with SZ (n = 35), their unaffected siblings (SB, n = 36) and healthy controls (HC, n = 47). We used a random forest algorithm that included biomarkers related to aging: eotaxins CCL-11 and CCL-24; the oxidative stress markers thiobarbituric acid-reactive substances (TBARS), protein carbonyl content (PCC), glutathione peroxidase (GPx); and telomere length (TL). The ML algorithm of biomarkers was able to distinguish individuals with SZ from HC with prediction accuracy of 79.7%, SZ from SB with 62.5% accuracy and SB from HC with 75.5% accuracy. These results support the hypothesis that a pathological accelerated aging might occur in SZ, and this pathological aging could be an endophenotype of the disease, once this profile was also observed in SB, suggesting that SB might suffer from an accelerated aging in some level.

Disentangling Cognitive Heterogeneity in Psychotic Spectrum Disorders

Neuropsychological impairments represent a central feature of psychosis-spectrum disorders. It is characterized by a great both within- and between-subjects variability (i.e. cognitive heterogeneity), which needs to be better disentangled. The present study aimed to describe the distribution of performance on the Brief Assessment of Cognition in Schizophrenia (BACS) by using the Equivalent Scores, in order to balance statistical methodological problems. To do so, cognitive performance groups were branded, identifying the main factors contributing to cognitive heterogeneity. A sample of 583 patients with a diagnosis of Schizophrenia or Psychotic Disorder Not Otherwise Specified was enrolled and assessed for neurocognition and intellectual level. K-means cluster analysis was performed based on BACS Equivalent Scores. Differences among clusters were analyzed throughout Analysis of Variance and Discriminant Function Analysis in order to identify the most significant predictors of cluster membership. For each cognitive task, roughly 40% of patients displayed poor performance, while up to 63% displayed a symbol-coding deficit. K-means cluster analysis depicted three profiles characterized by "near-normal" cognition, widespread impairment, and "borderline" profile. Discriminant analysis selected Verbal IQ and diagnosis as predictors of cluster membership. Our findings support the usefulness of Equivalent Scores and cluster analysis to explain cognitive heterogeneity, and tailor better interventions.

Cognitive profiles of healthy siblings of first-episode schizophrenia patients

AIM

Cognitive deficit in psychotic illness is intensively studied, different cognitive subtypes have been suggested. In recent years, there has been an increase in the number of studies in patients with schizophrenia and their relatives searching for endophenotypes of the disease. The aim of our study was to investigate cognitive performance and cognitive subtypes in the siblings of the patients.

METHODS

Four groups of subjects were included: patients with a first episode of psychotic illness, the siblings of these patients, and two control groups. All the study subjects (N = 84) had a battery of neuropsychological tests that measured basic cognitive domains - memory, executive functions, attention, visual-spatial skills, language skills and psychomotor speed - administered to them. The data were assessed with pairwise t-tests for group comparisons. The siblings were distributed into three groups according to their cognitive performance: non-deficit, partial deficit, and global deficit. Subsequently, the patients were assigned into three groups corresponding to their siblings' performance.

RESULTS

Our results revealed attenuation of abstract thinking in the siblings compared to the controls. As expected, the patients showed impairment across all cognitive domains. The patients and siblings demonstrated similar profiles in each subtype, in the severity of their impairment, and in their patterns of cognitive performance.

CONCLUSIONS

Our results suggest that the cognitive profile can be considered as an endophenotype of psychotic disorders.

Cannabidiol and Amisulpride Improve Cognition in Acute Schizophrenia in an Explorative, Double-Blind, Active-Controlled, Randomized Clinical Trial

Cannabidiol (CBD), a principal phytocannabinoid constituent, has demonstrated antipsychotic properties in recent clinical trials. While it has also been suggested a promising candidate for the treatment of neurodegenerative disorders, it failed to demonstrate efficacy in cognitive impairments associated with schizophrenia as an add-on treatment (600 mg/day for 6 weeks) in 18 chronically ill patients co-treated with a variety of psychopharmacologic drugs. Here, we report on the results of parallel-group, active-controlled, mono-therapeutic, double-blind, randomized clinical trial (CBD-CT1; ClinicalTrials.gov identifier: NCT00628290) in 42 acute paranoid schizophrenic patients receiving either CBD (up to 800 mg/day) or amisulpride (AMI, up to 800 mg/day) for four weeks in an inpatient setting with neurocognition as a secondary objective. Twentynine patients (15 and 14 in the CBD and AMI group, respectively) completed two cognitive assessments at baseline and the end of the treatment period. We investigated the following cognitive domains: pattern recognition, attention, working memory, verbal and visual memory and learning, processing speed, and verbal executive functions. When applying the Bonferroni correction for multiple testing, p < 0.0004 would indicate statistical significance. There was no relevant difference in neurocognitive performance between the CBD and the AMI group at baseline, and we observed no post-treatment differences between both groups. However, we observed improvements within both groups from pre-to post-treatment (standardized differences reported as Cohen’s d) in visual memory (CBD: 0.49, p = 0.015 vs. AMI: 0.63, p = 0.018) and processing speed (CBD: 0.41, p = 0.004 vs. AMI: 0.57, p = 0.023). Furthermore, CBD improved sustained attention (CBD: 0.47, p = 0.013, vs. AMI: 0.52, p = 0.085), and visuomotor coordination (CBD: 0.32, p = 0.010 vs. AMI: 0.63, p = 0.088) while AMI led to enhanced working memory performance in two different paradigms (Subject Ordered Pointing Task–AMI: 0.53, p = 0.043 vs. CBD: 0.03, p = 0.932 and Letter Number Sequencing–AMI: 0.67, p = 0.017 vs. CBD: 0.08 p = 0.755). There was no relevant correlation between changes in neurocognitive parameters and psychotic symptoms or anandamide serum levels. This study shows that both CBD and AMI improve neurocognitive functioning with comparable efficacy in young and acutely ill schizophrenia patients via an anandamide-independent mechanism.

Association of schizophrenia polygenic risk score with data-driven cognitive subtypes: A six-year longitudinal study in patients, siblings and controls

Cross-sectional studies have shown that the polygenic risk score for schizophrenia (PRS_SCZ) may influence heterogeneity in cognitive performance although evidence from family-based longitudinal study is limited. This study aimed to identify trajectories of cognitive function and assess whether the PRS_SCZ is associated with baseline cognitive performance and predicted six-year trajectories. We included 1119 patients with a schizophrenia spectrum disorder, and 1059 unaffected siblings and 586 unrelated controls who are eligible at baseline. Genotype data were collected at baseline, whereas clinical and sociodemographic data were collected at baseline, three and six years. Group-based trajectory modeling was applied on a weighted standardized composite score of general cognition to unravel cognitive subtypes and explore trajectories over time. We followed a standard procedure to calculate the polygenic risk score. A random-effects ordinal regression model was used to investigate the association between PRS_SCZ and cognitive subtypes. Five cognitive subtypes with variable trajectories were found in patients, four in siblings and controls, and six in all combined samples. PRS_SCZ significantly predicted poor cognitive trajectories in patients, siblings and all samples. After Bonferroni correction and adjustment for non-genetic factors, only the results in all combined sample remained significant. Cognitive impairment in schizophrenia is heterogeneous and may be linked with high PRS_SCZ. Our finding confirmed at least in all combined samples the presence of genetic overlap between schizophrenia and cognitive function and can give insight into the mechanisms of cognitive deficits.

A systematic review and narrative synthesis of data-driven studies in schizophrenia symptoms and cognitive deficits

To tackle the phenotypic heterogeneity of schizophrenia, data-driven methods are often applied to identify subtypes of its symptoms and cognitive deficits. However, a systematic review on this topic is lacking. The objective of this review was to summarize the evidence obtained from longitudinal and cross-sectional data-driven studies in positive and negative symptoms and cognitive deficits in patients with schizophrenia spectrum disorders, their unaffected siblings and healthy controls or individuals from general population. Additionally, we aimed to highlight methodological gaps across studies and point out future directions to optimize the translatability of evidence from data-driven studies. A systematic review was performed through searching PsycINFO, PubMed, PsycTESTS, PsycARTICLES, SCOPUS, EMBASE and Web of Science electronic databases. Both longitudinal and cross-sectional studies published from 2008 to 2019, which reported at least two statistically derived clusters or trajectories were included. Two reviewers independently screened and extracted the data. In this review, 53 studies (19 longitudinal and 34 cross-sectional) that conducted among 17,822 patients, 8729 unaffected siblings and 5520 controls or general population were included. Most longitudinal studies found four trajectories that characterized by stability, progressive deterioration, relapsing and progressive amelioration of symptoms and cognitive function. Cross-sectional studies commonly identified three clusters with low, intermediate (mixed) and high psychotic symptoms and cognitive profiles. Moreover, identified subgroups were predicted by numerous genetic, sociodemographic and clinical factors. Our findings indicate that schizophrenia symptoms and cognitive deficits are heterogeneous, although methodological limitations across studies are observed. Identified clusters and trajectories along with their predictors may be used to base the implementation of personalized treatment and develop a risk prediction model for high-risk individuals with prodromal symptoms.

Identifying the cognitive underpinnings of voice-hearing by comparing never, past and current voice-hearers

OBJECTIVE

The current study aimed to compare specific cognitive profiles corresponding to auditory verbal hallucinations (AVH) status and elucidate which pattern of cognitive deficits may predict voice-hearing status.

METHOD

Clinical participants with schizophrenia spectrum disorders were partitioned into: (i) current voice-hearers (n = 46), (ii) past voice-hearers (n = 37) and (iii) never voice-hearers (n = 40), and compared with 319 non-clinical controls. Cognitive assessment employed the MATRICS Consensus Cognitive Battery (MCCB), supplemented by the Delis-Kaplan Executive Function System (D-KEFS) Colour-Word Interference Test (Stroop) as a robust measure of executive function.

RESULTS

On the Visual Learning domain, current and past voice-hearers had significantly poorer performance relative to never voice-hearers, who in turn had significantly poorer performance than non-clinical controls. Current and never voice-hearers had significantly poorer performance on the Social Cognition domain relative to non-clinical controls. Current voice-hearers also had significantly poorer performance on the Inhibition domain relative to non-clinical controls. Binary logistic regression revealed that Visual Learning was the only significant cognitive predictor of AVH presence.

CONCLUSION

Visual learning, and potentially inhibition, may be viable therapeutic targets when addressing cognitive mechanisms associated with AVHs. Future research should focus on investigating additional cognitive mechanisms, employing diverse voice-hearing populations and embarking on related longitudinal studies.

The Use of Cognitive Screening in Pharmacotherapy Trials for Cognitive Impairment Associated With Schizophrenia

There are currently no regulatory approved pharmacological treatments for cognitive impairment associated with schizophrenia (CIAS). One possibility is that trial methodology itself is hindering their development. Emerging evidence suggests that patients with schizophrenia may show limited benefit from pro-cognitive interventions if they already exhibit intact cognitive performance, relative to normative thresholds. The aim of this report was to examine the extent to which objectively assessed cognitive performance has been used as an eligibility and/or stratification criterion in CIAS pharmacotherapy trials. On 16^th January 2019, we conducted a systematic search of studies listed on ClinicalTrials.gov to identify randomized, double-blind, placebo-controlled, add-on pharmacotherapy trials conducted in patients with a diagnosis of schizophrenia, in which a paper-and-pencil or computerized cognitive task (or battery) was specified as a primary outcome measure. Of the 87 trials that met our inclusion criteria, 10 (11.5%) required the presence of an objectively assessed cognitive deficit as part of their patient eligibility criteria. No studies reported stratifying patients according to the presence or degree of cognitive impairment they exhibited. These results suggest that the vast majority of CIAS trials may have been underpowered due to the inclusion of cognitively "normal" patients. Purposive screening for cognitive impairment could increase CIAS trial success.

Long-term cognitive trajectories and heterogeneity in patients with schizophrenia and their unaffected siblings

OBJECTIVE

This study aimed to assess the heterogeneity and stability of cognition in patients with a non-affective psychotic disorder and their unaffected siblings. In addition, we aimed to predict the cognitive subtypes of siblings by their probands.

METHOD

Assessments were conducted at baseline, 3 and 6 years in 1119 patients, 1059 siblings and 586 controls from the Genetic Risk and Outcome of Psychosis (GROUP) study. Group-based trajectory modeling was applied to identify trajectories and clustered multinomial logistic regression analysis was used for prediction modeling. A composite score of eight neurocognitive tests was used to measure cognitive performance.

RESULTS

Five stable cognitive trajectories ranging from severely altered to high cognitive performance were identified in patients. Likewise, four stable trajectories ranging from moderately altered to high performance were found in siblings. Siblings had a higher risk of cognitive alteration when patients' alteration was mild (OR = 2.21), moderate (OR = 5.70), and severe (OR = 10.07) compared with patients with intact cognitive function. The familial correlation coefficient between pairs of index patients and their siblings was 0.27 (P = 0.003).

CONCLUSIONS

The cognitive profiles identified in the current study might be suitable as endophenotypes and could be used in future genetic studies and predicting functional and clinical outcomes.