Developmental trajectory of cognitive impairment in bipolar disorder: comparison with schizophrenia

Executive functions in non-suicidal self-injury comorbid first-episode and drug-naïve depression among adolescents

Executive functions(EFs) may be associated with the emergence of non-suicidal self-injury(NSSI) due to their role as behavior controllers. EFs includes three core cognitive processes: inhibitory control, working memory, and cognitive flexibility(i.e. the ability to selectively alter cognitive strategies to generate appropriate behavior in the changing environment). This study aimed to systematically explore the three core EFs in depressed adolescents with NSSI. The data was obtained from the baseline data of the Chinese adolescent depression Cohort. The adolescents underwent cognitive assessments to yield domain-specific scores in EFs using the Digit Span Backward test(DSB), the Stroop Color-word interference test- color-word condition(Stroop-CW), and the Wisconsin Card Sorting tests(WCST). The significant differences in WCST scores were found between the NSSI group and the non-NSSI group. NSSI frequency was moderately positively correlated with total errors and negatively correlated with the number of categories completed. The number of categories completed in the "≥200″ NSSI frequency group was significantly lower than that in the "≤10″ NSSI group. The current findings suggested that depressed adolescents who had engaged in NSSI have poorer cognitive flexibility performance compared to adolescents without NSSI. As the frequency of NSSI increased, cognitive flexibility might become worse. These results provide evidence of a connection between executive dysfunctions and NSSI in depressed adolescents.

Brain age and cognitive functioning in first-episode bipolar disorder

BACKGROUND

There is significant heterogeneity in cognitive function in patients with bipolar I disorder (BDI); however, there is a dearth of research into biological mechanisms that might underlie cognitive heterogeneity, especially at disease onset. To this end, this study investigated the association between accelerated or delayed age-related brain structural changes and cognition in early-stage BDI.

METHODS

First episode patients with BDI (n = 80) underwent cognitive assessment to yield demographically normed composite global and domain-specific scores in verbal memory, non-verbal memory, working memory, processing speed, attention, and executive functioning. Structural magnetic resonance imaging data were also collected from all participants and subjected to machine learning to compute the brain-predicted age difference (brainPAD), calculated by subtracting chronological age from age predicted by neuroimaging data (positive brainPAD values indicating age-related acceleration in brain structural changes and negative values indicating delay). Patients were divided into tertiles based on brainPAD values, and cognitive performance compared amongst tertiles with ANCOVA.

RESULTS

Patients in the lowest (delayed) tertile of brainPAD values (brainPAD range -17.9 to -6.5 years) had significantly lower global cognitive scores (p = 0.025) compared to patients in the age-congruent tertile (brainPAD range -5.3 to 2.4 yrs), and significantly lower verbal memory scores (p = 0.001) compared to the age-congruent and accelerated (brainPAD range 2.8 to 16.1 yrs) tertiles.

CONCLUSION

These results provide evidence linking cognitive dysfunction in the early stage of BDI to apparent delay in typical age-related brain changes. Further studies are required to assess how age-related brain changes and cognitive functioning evolve over time.

Effectiveness of enhancing cognitive reserve in children, adolescents and young adults at genetic risk for psychosis: Study protocol for a randomized controlled trial

BACKGROUND

Offspring of patients diagnosed with bipolar disorder and schizophrenia (Off-BDSZ) have a high genetic risk of developing a mental illness. The aim of this project is to develop and investigate the efficacy of an intervention aimed at this population, based on the concept of cognitive reserve.

METHODS

This is a multicenter randomized trial with an experimental test-retest design study with control group. Two groups will be included: a community comparison group (CC) and a Off-BDSZ group. A total of 108 Off-BDSZ and 65 CC aged between 6 and 25 years will be recruited. Off-BDSZ participants will be randomized to receive either Cognitive Reserve EnhAncement ThErapy (CREATE) (n=54), or a supportive approach (n=54). The CC group will be assessed at baseline. The duration of the intervention will be 3 months, with 12 weekly group sessions. The primary outcome will be the improvement in CR measured according to change in the Cognitive Reserve Assessment Scale in Health (CRASH) and Cognitive Reserve scale for Adolescents (CORE-A). All participants will be blindly evaluated using clinical, cognitive and neuroimaging measures at baseline, at three months (after the psychological intervention), and at twelve-month follow-up after treatment completion.

DISCUSSION

The results will provide insight into whether the CREATE-Offspring version may enhance cognitive reserve (CR) in child, adolescent and young adult Off-BDSZ as well as advance knowledge about changes in clinical manifestations, neuropsychological performance and brain structure and function associated with improving CR. This novel and cost-effective intervention represents an advance in the framework of preventive interventions in mental health.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03722082. Registered on 26 October 2018.

Clinical and developmental characteristics of cognitive subgroups in a transdiagnostic sample of schizophrenia spectrum disorders and bipolar disorder

Evidence suggests that neurocognitive dysfunction is a transdiagnostic feature of individuals across the continuum between schizophrenia and bipolar disorder. However, there is significant heterogeneity of neuropsychological and social-cognitive abilities in schizophrenia, schizoaffective disorder, and bipolar disorder. The current study aimed to investigate the clinical and developmental characteristics of cognitive subgroups within the schizo-bipolar spectrum. 147 clinically stable patients with schizophrenia, schizoaffective or bipolar disorder were assessed using clinical rating scales for current psychotic and affective symptoms, and a comprehensive neuropsychological battery including measures of social cognition (Hinting and Reading the mind from the Eyes (RMET) task)). Developmental history and premorbid academic functioning were also evaluated. The study also included 36 healthy controls. Neurocognitive subgroups were investigated using latent class analysis (LCA). The optimal number of clusters was determined based on the Bayesian information criterion. A logistic regression analysis was conducted to investigate the predictors of membership to the globally impaired subgroup. LCA revealed two neurocognitive clusters including globally impaired (n = 89, 60.5%) and near-normal cognitive functioning (n = 58, 39.5%) subgroups. The near-normal cognitive functioning subgroup was not significantly different from healthy controls. The globally impaired subgroup had a higher score of developmental abnormalities (p<0.001), poorer premorbid academic functioning, mothers who were less educated and more severe disorganized speech (p = 0.001) and negative symptoms (p = 0.004) compared to the near-normal cognitive functioning group. History of developmental abnormalities and persistent disorganization rather than diagnosis are significant predictors of the subgroup of individuals with global cognitive impairment in the schizophrenia-bipolar disorder continuum.

Low α-N-acetylgalactosaminidase plasma concentration correlates with the presence and severity of the bipolar affective disorder

OBJECTIVES

Believing that a neurodevelopmental pathology may cause bipolar affective disorder (BAD), we aimed to measure the concentrations of α-N-acetylgalactosaminidase (α-NAGAL), a lysosomal enzyme.

METHODS

The study included 32 patients with BAD and 32 healthy controls. The Young Mania Rating Scale was used to measure the severity of the disease. Serum α-N-acetylgalactosaminidase concentrations were measured in all blood samples using the human α-N-acetylgalactosaminidase ELISA Kit.

RESULTS

A statistically significant difference was found in the α-NAGAL values between the groups. The mean α-NAGAL values of BAD patients are lower than the mean α-NAGAL values of the control group. A strong negative and statistically significant relationship was found between the α-NAGAL values of patients with BAD and their Young Mania Rating Scale scores. And a positive strong correlation was found between the age of onset of the disease and α-NAGAL levels.

CONCLUSIONS

Low α-N-acetylgalactosaminidase concentrations may cause the accumulation of some glycoproteins in the lysosomes in the brain during the gestational period, producing the clinical symptoms of BAD. α-N-acetylgalactosaminidase deficiency may not be the only cause of BAD, but it may be an important factor in the aetiology of this disease.

Minor physical anomalies in bipolar disorder in comparison to healthy controls and schizophrenia: A systematic review and meta-analysis

Minor physical anomalies (MPAs) are markers of abnormalities in early foetal development and are well established findings in schizophrenia. It has been suggested that neurodevelopmental abnormalities might play a role not only in schizophrenia but also in bipolar disorder (BD). Therefore, according to neurodevelopmental theory of BD, one might expect increased prevalence of MPAs in BD. A meta-analysis of 11 studies was conducted to quantitatively review MPAs in BD in comparison to schizophrenia and healthy controls. The current meta-analysis compared MPA scores of 584 BD patients and 723 healthy controls, and 401 BD and 612 schizophrenia patients. Patients with BD had significantly higher MPA scores than healthy controls (g=0.47, CI=0.28-0.67). This was true both for craniofacial (g=0.57, CI=0.34-0.79) and periphery (g=0.46, CI=0.18-0.73) MPAs. BD was associated with a less severe increase in MPA score compared to schizophrenia, however, between-group difference was small (g=0.19, CI=0.05-0.33). The outcome of this meta-analysis suggests that BD is associated with medium effect size increase in MPAs which is only minimally less severe than schizophrenia. This finding supports the hypothesis that early developmental insult in brain development plays a role not only in schizophrenia but also BD. Studies investigating clinical, neurocognitive, neuroanatomical and other biological correlates of MPAs in BD might helpful in characterizing subtype (s) of BD that is associated with pronounced deviations in brain development.

Clinical and cortical similarities identified between bipolar disorder I and schizophrenia: A multivariate approach

BACKGROUND

Structural neuroimaging studies have identified similarities in the brains of individuals diagnosed with schizophrenia (SZ) and bipolar I disorder (BP), with overlap in regions of gray matter (GM) deficits between the two disorders. Recent studies have also shown that the symptom phenotypes associated with SZ and BP may allow for a more precise categorization than the current diagnostic criteria. In this study, we sought to identify GM alterations that were unique to each disorder and whether those alterations were also related to unique symptom profiles.

MATERIALS AND METHODS

We analyzed the GM patterns and clinical symptom presentations using independent component analysis (ICA), hierarchical clustering, and n-way biclustering in a large (N ∼ 3,000), merged dataset of neuroimaging data from healthy volunteers (HV), and individuals with either SZ or BP.

RESULTS

Component A showed a SZ and BP < HV GM pattern in the bilateral insula and cingulate gyrus. Component B showed a SZ and BP < HV GM pattern in the cerebellum and vermis. There were no significant differences between diagnostic groups in these components. Component C showed a SZ < HV and BP GM pattern bilaterally in the temporal poles. Hierarchical clustering of the PANSS scores and the ICA components did not yield new subgroups. N-way biclustering identified three unique subgroups of individuals within the sample that mapped onto different combinations of ICA components and symptom profiles categorized by the PANSS but no distinct diagnostic group differences.

CONCLUSION

These multivariate results show that diagnostic boundaries are not clearly related to structural differences or distinct symptom profiles. Our findings add support that (1) BP tend to have less severe symptom profiles when compared to SZ on the PANSS without a clear distinction, and (2) all the gray matter alterations follow the pattern of SZ < BP < HV without a clear distinction between SZ and BP.

Segregation, integration and balance in resting-state brain functional networks associated with bipolar disorder symptoms

Bipolar disorder (BD) is a serious mental disorder involving widespread abnormal interactions between brain regions, and it is believed to be associated with imbalanced functions in the brain. However, how this brain imbalance underlies distinct BD symptoms remains poorly understood. Here, we used a nested-spectral partition (NSP) method to study the segregation, integration, and balance in resting-state brain functional networks in BD patients and healthy controls (HCs). We first confirmed that there was a high deviation in the brain functional network toward more segregation in BD patients than in HCs and that the limbic system had the largest alteration. Second, we demonstrated a network balance of segregation and integration that corresponded to lower anxiety in BD patients but was not related to other symptoms. Subsequently, based on a machine-learning approach, we identified different system-level mechanisms underlying distinct BD symptoms and found that the features related to the brain network balance could predict BD symptoms better than graph theory analyses. Finally, we studied attention-deficit/hyperactivity disorder (ADHD) symptoms in BD patients and identified specific patterns that distinctly predicted ADHD and BD scores, as well as their shared common domains. Our findings supported an association of brain imbalance with anxiety symptom in BD patients and provided a potential network signature for diagnosing BD. These results contribute to further understanding the neuropathology of BD and to screening ADHD in BD patients.

Different Frequency of Heschl’s Gyrus Duplication Patterns in Neuropsychiatric Disorders: An MRI Study in Bipolar and Major Depressive Disorders

An increased prevalence of duplicated Heschl’s gyrus (HG) has been repeatedly demonstrated in various stages of schizophrenia as a potential neurodevelopmental marker, but it remains unknown whether other neuropsychiatric disorders also exhibit this macroscopic brain feature. The present magnetic resonance imaging study aimed to examine the disease specificity of the established finding of altered HG patterns in schizophrenia by examining independent cohorts of bipolar disorder (BD) and major depressive disorder (MDD). Twenty-six BD patients had a significantly higher prevalence of HG duplication bilaterally compared to 24 age- and sex-matched controls, while their clinical characteristics (e.g., onset age, number of episodes, and medication) did not relate to HG patterns. No significant difference was found for the HG patterns between 56 MDD patients and 33 age- and sex-matched controls, but the patients with a single HG were characterized by more severe depressive/anxiety symptoms compared to those with a duplicated HG. Thus, in keeping with previous findings, the present study suggests that neurodevelopmental pathology associated with gyral formation of the HG during the late gestation period partly overlaps between schizophrenia and BD, but that HG patterns may make a somewhat distinct contribution to the phenomenology of MDD.

Clinical Value of Inflammatory and Neurotrophic Biomarkers in Bipolar Disorder: A Systematic Review and Meta-Analysis

Bipolar disorder (BD) is a multifactorial chronic psychiatric disease highly defined by genetic, clinical, environmental and social risk factors. The present systematic review and meta-analysis aimed to examine the relationship between inflammatory and neurotrophic factors and clinical, social and environmental factors involved in the development and the characterization of BD. Web of Science, PubMed, PsycINFO, Scopus and Science Direct were searched by two independent reviewers. The systematic review was registered in PROSPERO (CRD42020180626). A total of 51 studies with 4547 patients with a diagnosis of BD were selected for systematic review. Among them, 18 articles were included for meta-analysis. The study found some evidence of associations between BDNF and/or inflammatory factors and different stressors and functional and cognitive impairment, but limitations prevented firm conclusions. The main finding of the meta-analysis was a negative correlation between circulating levels of BDNF and depression severity score (standardized mean difference = −0.22, Confidence Interval 95% = −0.38, −0.05, p = 0.01). Evidence indicates that BDNF has a role in the depressive component of BD. However, the poor consistency found for other inflammatory mediators clearly indicates that highly controlled studies are needed to identity precise biomarkers of this disorder.

Association between lifetime and recent stressful life events and the early course and psychopathology in patients with newly diagnosed bipolar disorder, first-degree unaffected relatives and healthy controls: Cross-sectional results from a prospective study

OBJECTIVE

There is an accumulation of stressful life events prior to the first mood episode, but the impact of previous severe life events on psychopathology in patients with bipolar disorder (BD) is not well studied. We aimed to examine the number of recent and lifetime life events in patients with newly diagnosed BD, their unaffected relatives (UR), and healthy controls (HC) as well as the impact of severe lifetime life events on the early course of BD.

METHODS

We compared the number of recent and lifetime life events in 398 patients with newly diagnosed BD, 109 UR, and 214 HC. We subsequently dichotomized the patients with BD by >2 lifetime life events to investigate the associations of severe lifetime life events with clinical characteristics and affective symptoms.

RESULTS

Patients with newly diagnosed BD reported significantly more life events in the last 12 months and lifetime before compared with UR and HC. Patients who reported >2 lifetime life events (n = 160) compared with patients with 0-2 life events (n = 238) had a significantly longer diagnostic delay (9.5 years ± 8.2 vs. 6.2 years ± 6.9), presented with more anxiety and depressive symptoms and had at least one previous suicide attempt (30.6% vs. 15.6%) and one previous admission (51.3% vs. 36.6%).

CONCLUSION

The experience of severe lifetime life events seems to impact the early course in BD in terms of longer diagnostic delay, more severe psychopathology including more admissions and a more than doubled risk for previous suicide attempts.

What we learn about bipolar disorder from large-scale neuroimaging: Findings and future directions from the ENIGMA Bipolar Disorder Working Group

MRI-derived brain measures offer a link between genes, the environment and behavior and have been widely studied in bipolar disorder (BD). However, many neuroimaging studies of BD have been underpowered, leading to varied results and uncertainty regarding effects. The Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) Bipolar Disorder Working Group was formed in 2012 to empower discoveries, generate consensus findings and inform future hypothesis-driven studies of BD. Through this effort, over 150 researchers from 20 countries and 55 institutions pool data and resources to produce the largest neuroimaging studies of BD ever conducted. The ENIGMA Bipolar Disorder Working Group applies standardized processing and analysis techniques to empower large-scale meta- and mega-analyses of multimodal brain MRI and improve the replicability of studies relating brain variation to clinical and genetic data. Initial BD Working Group studies reveal widespread patterns of lower cortical thickness, subcortical volume and disrupted white matter integrity associated with BD. Findings also include mapping brain alterations of common medications like lithium, symptom patterns and clinical risk profiles and have provided further insights into the pathophysiological mechanisms of BD. Here we discuss key findings from the BD working group, its ongoing projects and future directions for large-scale, collaborative studies of mental illness.

Affective episodes in recently diagnosed patients with bipolar disorder associated with altered working memory-related prefrontal cortex activity: A longitudinal fMRI study

INTRODUCTION

Bipolar disorder (BD) is often accompanied by trait-related cognitive impairments, but it is unclear which neurocircuitry abnormalities give rise to these impairments and whether neurocircuitry differences are exacerbated with illness progression. This longitudinal fMRI study of recently diagnosed BD patients investigates whether aberrant working memory (WM) related activity in the cognitive control network is accentuated by new affective episodes.

METHODS

Forty-seven recently diagnosed BD patients in full or partial remission and 38 healthy controls were assessed with neurocognitive tests and fMRI during the performance of a verbal n-back WM task at baseline and follow-up (15.4 months in average).

RESULTS

Patients showed WM-related hypo-activity in dorsal prefrontal cortex (dPFC) and impaired cognitive function within attention and psychomotor speed, WM and executive function, and verbal learning and memory compared to controls at baseline. During the follow-up period, 26 patients experienced at least one affective episode (BD+), while 21 remained in remission (BD-). There was no deterioration in cognitive performance in BD+ compared to BD- patients. Nevertheless, BD+ displayed increased WM-related dPFC activity at follow-up compared with BD- patients. This change in dPFC response was independent of mood symptoms and medication.

LIMITATIONS

The study did not account for type or frequency of affective episodes.

CONCLUSION

The study identifies cognitive impairment and WM-related hypo-activity in dPFC early during the course of BD. Increased high-load WM related dPFC activity over the follow-up period in BD+ versus BD- patients in the absence of changes in cognitive performance may reflect an episode-related reduction in PFC efficiency.

The effect of concomitant benzodiazepine use on neurocognition in stable, long-term patients with bipolar disorder

OBJECTIVE

Neurocognitive dysfunction is a common feature of bipolar disorder even in euthymia, and psychopharmacological treatment could have an effect on cognition. Long-term prescription of benzodiazepines in bipolar disorder is a common practice, and their effect on neurocognition has not been well studied in this population. The aim of this study was to evaluate the impact of concomitant benzodiazepine long-term use on neurocognitive function in stable euthymic bipolar disorder patients.

METHODS

Seventy-three euthymic bipolar disorder outpatients and 40 healthy individuals were assessed using a neurocognitive battery. Patients were classified in two groups according to the presence of benzodiazepines in their treatment: the benzodiazepine group (n = 34) and the non- benzodiazepine group (n = 39). Neurocognitive performance was compared between the groups using a multivariate analysis of covariance, considering age, number of depressive episodes, adjuvant antipsychotic drugs, Young Mania Rating Scale score and Hamilton Depression Rating Scale score as covariates.

RESULTS

Both bipolar disorder groups (benzodiazepine and non-benzodiazepine) showed an impairment in memory domains (Immediate Visual Memory [p = 0.013], Working Memory [p < 0.001], and Letter-Number Sequence [p < 0.001] from the Wechsler Memory Scale-Revised-III) and slower processing speed functions (Stroop Colour [p < 0.001]) relative to the control group. Nevertheless, the benzodiazepine group showed a greater impairment in executive functions (Conceptual Level Responses [p = 0.024] from the Wisconsin Card Sorting Test and Frontal Assessment Battery [p = 0.042]).

CONCLUSION

Although memory and processing speed impairments were found in bipolar disorder, regardless of their benzodiazepine treatment, benzodiazepine users presented additional neurocognitive impairments in terms of executive functioning. These findings support restricted prescription of benzodiazepines in individuals with bipolar disorder.

The Heterogeneity of Longitudinal Cognitive Decline in Euthymic Bipolar I Disorder With Clinical Characteristics and Functional Outcomes

We characterized the heterogeneity and risk factors of cognitive decline in euthymic bipolar disorder (BD), and their magnitude of associations with subjective daily functions. In this retrospective cohort, BD type I patients (N = 128) were followed for an average of 6.5 years. Intelligence quotient (IQ) at index date was recorded, and premorbid IQ was estimated. We used Brief Assessment of Cognition in Affective Disorders (BAC-A) to assess cognition at follow-up. We evaluated current functions with World Health Organization Disability Assessment Schedule 2.0. Clinical and sociodemographic factors were examined for their independent effects on longitudinal cognitive decline. In addition, we employed multivariate adaptive regression spline to detect inflection points for the nature of slope changes in cognitive decline among BD patients. During follow-up years, 21 BD patients (16.4%) showed longitudinal cognitive decline. In cognitive decline group, all cognitive domains of BAC-A were significantly worsened. We found that density of episodes with psychotic features was an independent risk factor for cognitive decline after adjusted for age, gender and dose of mood stabilizer. After the age of 42 years, a steeper cognitive change was observed in the cognitive decline group. The correlation pattern between cognitive domains and functional outcomes differed between patients with and without cognitive decline. The present study characterized cognitive heterogeneity longitudinally in BD patients. As density of episodes play roles for cognitive decline, our results emphasize the importance of relapse prevention. Our findings provide hints for future personalized interventions and facilitating genetic and biological studies for dissecting the heterogeneity of bipolar illness.

Mapping brain-behavior space relationships along the psychosis spectrum

Difficulties in advancing effective patient-specific therapies for psychiatric disorders highlight a need to develop a stable neurobiologically grounded mapping between neural and symptom variation. This gap is particularly acute for psychosis-spectrum disorders (PSD). Here, in a sample of 436 PSD patients spanning several diagnoses, we derived and replicated a dimensionality-reduced symptom space across hallmark psychopathology symptoms and cognitive deficits. In turn, these symptom axes mapped onto distinct, reproducible brain maps. Critically, we found that multivariate brain-behavior mapping techniques (e.g. canonical correlation analysis) do not produce stable results with current sample sizes. However, we show that a univariate brain-behavioral space (BBS) can resolve stable individualized prediction. Finally, we show a proof-of-principle framework for relating personalized BBS metrics with molecular targets via serotonin and glutamate receptor manipulations and neural gene expression maps derived from the Allen Human Brain Atlas. Collectively, these results highlight a stable and data-driven BBS mapping across PSD, which offers an actionable path that can be iteratively optimized for personalized clinical biomarker endpoints.

Transdiagnostic comparison of visual working memory capacity in bipolar disorder and schizophrenia

BACKGROUND

Impaired working memory is a core cognitive deficit in both bipolar disorder and schizophrenia. Its study might yield crucial insights into the underpinnings of both disorders on the cognitive and neurophysiological level. Visual working memory capacity is a particularly promising construct for such translational studies. However, it has not yet been investigated across the full spectrum of both disorders. The aim of our study was to compare the degree of reductions of visual working memory capacity in patients with bipolar disorder (PBD) and patients with schizophrenia (PSZ) using a paradigm well established in cognitive neuroscience.

METHODS

62 PBD, 64 PSZ, and 70 healthy controls (HC) completed a canonical visual change detection task. Participants had to encode the color of four circles and indicate after a short delay whether the color of one of the circles had changed or not. We estimated working memory capacity using Pashler's K.

RESULTS

Working memory capacity was significantly reduced in both PBD and PSZ compared to HC. We observed a small effect size (r = .202) for the difference between HC and PBD and a medium effect size (r = .370) for the difference between HC and PSZ. Working memory capacity in PSZ was also significantly reduced compared to PBD with a small effect size (r = .201). Thus, PBD showed an intermediate level of impairment.

CONCLUSIONS

These findings provide evidence for a gradient of reduced working memory capacity in bipolar disorder and schizophrenia, with PSZ showing the strongest degree of impairment. This underscores the importance of disturbed information processing for both bipolar disorder and schizophrenia. Our results are compatible with the cognitive manifestation of a neurodevelopmental gradient affecting bipolar disorder to a lesser degree than schizophrenia. They also highlight the relevance of visual working memory capacity for the development of both behavior- and brain-based transdiagnostic biomarkers.

Cognitive subgroups in first episode bipolar I disorder: Relation to clinical and brain volumetric variables

OBJECTIVE

Distinct cognitive subgroups are seen in patients with long duration bipolar I disorder (BDI), possibly reflective of underlying pathophysiological differences. It is unknown whether such cognitive heterogeneity is present at illness onset. We applied latent class analysis (LCA) to cognitive test scores in first episode BDI patients. Exploratory analysis elucidated whether impaired subgroups were characterized by 'early neurodevelopmental' (low premorbid IQ and intracranial volume) versus 'later neurodevelopmental' (decline from premorbid to current IQ, changes in relative grey (GM)/white (WM) matter volumes) pathology.

METHODS

Recently recovered first manic episode BDI patients (n = 91) and healthy controls (HC, n = 63) comprised the study sample. LCA identified subgroups based on processing speed, verbal memory, non-verbal memory, executive functioning, attention and working memory scores. Subgroups were compared amongst each other and HC on premorbid/current IQ, intracranial (ICV), total brain and regional volumes.

RESULTS

Three cognitive subgroups emerged: (i) globally impaired (GI, n = 31), scoring 0.5-1 SD below demographically corrected norms across domains, (ii) selectively impaired (SI, n = 47), with predominant processing speed deficits and (iii) high performing (HP, n = 13), with above-average cognitive performance. GI patients showed a 'later neurodevelopmental' pattern, with normal ICV, significant decline from premorbid to current IQ, higher total GM and lower total WM (with respect to total brain volume) versus SI and HC (p = 0.003). GI patients had higher left frontal pole GM versus HC (p < 0.05, FWE corrected).

CONCLUSIONS

A globally impaired patient subgroup is identifiable in first episode BDI, possibly characterized by unique neurodevelopmental pathologic processes proximal to illness onset.

Neuropsychological development in the child and adolescent offspring of patients diagnosed with schizophrenia or bipolar disorder: A two-year follow-up comparative study

There has been growing scientific evidence in recent years that schizophrenia and bipolar disorder share clinical, cognitive, neuroimaging and genetic characteristics. This overlap might also be present in their offspring, who have an increased risk of developing both disorders. Comparing the characteristics of these samples may have important implications for understanding etiological processes. This study aimed to assess the development of cognitive functions over two years in a sample of child and adolescent offspring of patients diagnosed with schizophrenia (SZoff) or bipolar disorder (BDoff), comparing them with a community control group (CCoff).

METHODS

90 BDoff, 41 SZoff and 107 CCoff aged between 6 and 17 years were included at baseline. At the two-year follow-up, 84.9% of the sample was re-assessed (78 BDoff, 32 SZoff and 92 CCoff). All subjects were assessed with a comprehensive neuropsychological test battery at baseline and at the two-year follow-up to evaluate: intelligence quotient, working memory, processing speed, verbal memory and learning, visual memory, executive functions and sustained attention.

RESULTS

Processing speed, verbal memory and executive functions showed different developmental patterns among the SZoff, BDoff and CCoff groups. The SZoff group maintained baseline performances in the three variables over time, while the BDoff group presented improved processing speed and executive functioning and the CCoff group showed improvements in verbal memory and executive functions at follow-up.

CONCLUSIONS

These findings suggest that the development of some cognitive functions might differ between child and adolescent SZoff and BDoff, indicating different trajectories during neurodevelopment.

Deficiencies in Theory of Mind in patients with schizophrenia, bipolar disorder, and major depressive disorder: A systematic review of secondary literature

Deficiencies in Theory of Mind (ToM) are consistently found in individuals with schizophrenia (SZ), major depressive disorder (MDD), and bipolar disorder (BD). However, the character of these deficits and their role in the pathogenesis of mental illness remains poorly understood. This systematic review synthesizes the available secondary literature pertaining to ToM functioning in individuals with MDD, BD, or SZ, and their respective spectrum disorders in order to delineate disorder or symptom specific patterns of ToM impairment. Literature suggests that ToM deficits increase in severity along the affective-psychotic spectrum, with mild deficits in patients with MDD, and severe deficits in patients with mania or psychosis. Furthermore, ToM deficits appear to be part of a broader developmental phenotype associated with SZ and BD, as suggested by findings of attenuated impairments in ToM in remitted patients with SZ or BD, unaffected first-degree relatives of patients, and clinical high-risk groups. Future psychiatric research on ToM should aim to disentangle relationships between ToM deficits and specific symptom dimensions transdiagnostically, and employ standardized, construct-specific ToM tasks.

Associations among childhood parenting, affective temperaments, depressive symptoms, and cognitive complaints in adult community volunteers

BACKGROUND

Correlations between depressive symptoms and affective temperaments or quality of childhood parenting have been investigated previously; however, how childhood parenting and affective temperaments affect cognitive complaints remains unknown. Thus, we evaluated correlations among childhood parenting, affective temperaments, depressive symptoms, and cognitive complaints in adults.

METHODS

Participants (N = 490) completed the Parental Bonding Instrument (PBI), Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Auto-questionnaire version (TEMPS-A), the Patient Health Questionnaire-9 (PHQ-9), and the Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA). Multiple regression analyses and structural equation modeling were performed to evaluate scale correlations.

RESULTS

As per structural equation modeling, the direct effect of PHQ-9 and four subscales (cyclothymic, depressive, irritable, and anxious temperament) of TEMPS-A on COBRA were significant; the indirect effect of the four subscales of TEMPS-A on COBRA via PHQ-9 was significant; the direct effect of the three subscales (paternal care, maternal care, and maternal overprotection) of PBI on PHQ-9 and four subscales of TEMPS-A were significant; the indirect effect of the three subscales of PBI on PHQ-9 via the four subscales of TEMPS-A was significant.

LIMITATIONS

Cross-sectional designs cannot identify causal relationships between parameters. As participants were adult volunteers from the community, results may not be generalizable to individuals with psychiatric disorders.

CONCLUSIONS

Childhood parenting affects cognitive complaints indirectly via affective temperaments and depressive symptoms in adult community volunteers. An important role of affective temperaments and depressive symptoms in the effects of childhood parenting on cognitive complaints is suggested.

Role of cognitive reserve in cognitive variability in euthymic individuals with bipolar disorder: cross-sectional cluster analysis

BACKGROUND

People with bipolar disorder have moderate cognitive difficulties that tend to be more pronounced during mood episodes but persist after clinical remission and affect recovery. Recent evidence suggests heterogeneity in these difficulties, but the factors underlying cognitive heterogeneity are unclear.

AIMS

To examine whether distinct cognitive profiles can be identified in a sample of euthymic individuals with bipolar disorder and examine potential differences between subgroups.

METHOD

Cognitive performance was assessed across four domains (i.e. processing speed, verbal learning/memory, working memory, executive functioning) in 80 participants. We conducted a hierarchical cluster analysis and a discriminant function analysis to identify cognitive profiles and considered differences in cognitive reserve, estimated cognitive decline from premorbid cognitive functioning, and clinical characteristics among subgroups.

RESULTS

Four discrete cognitive profiles were identified: cognitively intact (n = 25; 31.3%); selective deficits in verbal learning and memory (n = 15; 18.8%); intermediate deficits across all cognitive domains (n = 30; 37.5%); and severe deficits across all domains (n = 10; 12.5%). Cognitive decline after illness onset was greater for the intermediate and severe subgroups. Cognitive reserve scores were increasingly lower for subgroups with greater impairments. A smaller proportion of cognitively intact participants were using antipsychotic medications compared with all other subgroups.

CONCLUSIONS

Our findings suggest that individuals with cognitively impaired profiles demonstrate more cognitive decline after illness onset. Cognitive reserve may be one of the factors underlying cognitive variability across people with bipolar disorder. Patients in the intermediate and severe subgroups may be in greater need of interventions targeting cognitive difficulties.

The Dutch Bipolar Offspring Study: Cognitive Development and Psychopathology

Various aspects of the relationship between cognitive impairment and bipolar disorder are not clear yet. This study examines cognitive and educational functioning prospectively in offspring at familial risk for bipolar disorder, in order to improve our understanding of the association between cognitive functioning and psychopathology. Bipolar offspring (N = 92) from the prospective Dutch bipolar offspring study were evaluated at adolescence and adulthood for IQ estimate, educational achievement and development of any psychiatric disorder. The main outcome was IQ estimate after 12 years of follow-up (offspring mean age 28 years). Generalized estimating equation (GEE) analyses showed that any lifetime DSM-IV axis I diagnosis was related to a lower cognitive outcome at adulthood as compared to unaffected bipolar offspring. No specific association was found for type of diagnosis. Early onset psychopathology (diagnosis at or before age 15 years) was significantly related to lower IQ estimate at adulthood, indicating a sensitive period for neurocognitive development.

Cognitive Heterogeneity across Schizophrenia and Bipolar Disorder: A Cluster Analysis of Intellectual Trajectories

OBJECTIVE

Cognitive dysfunction cut across diagnostic categories and is present in both schizophrenia and bipolar disorder, although with considerable heterogeneity in both disorders. This study examined if distinct cognitive subgroups could be identified across schizophrenia and bipolar disorder based on the intellectual trajectory from the premorbid phase to after illness onset.

METHOD

Three hundred and ninety-eight individuals with schizophrenia (n = 223) or bipolar I disorder (n = 175) underwent clinical and neuropsychological assessment. Hierarchical and k-means cluster analyses using premorbid (National Adult Reading Test) and current IQ (Wechsler Abbreviated Scale of Intelligence) estimates were performed for each diagnostic category, and the whole sample collapsed. Resulting clusters were compared on neuropsychological, functional, and clinical variables. Healthy controls (n = 476) were included for analyses of neuropsychological performance.

RESULTS

Cluster analyses consistently yielded three clusters: a relatively intact group (36% of whole sample), an intermediate group with mild cognitive impairment (44%), and an impaired group with global deficits (20%). The clusters were validated by multinomial logistic regression and differed significantly for neuropsychological, functional, and clinical measures. The relatively intact group (32% of the schizophrenia sample and 42% of the bipolar sample) performed below healthy controls for speeded neuropsychological tests.

CONCLUSIONS

Three cognitive clusters were identified across schizophrenia and bipolar disorder using premorbid and current IQ estimates. Groups differed for clinical, functional, and neuropsychological variables, implying their meaningfulness. One-third of the schizophrenia sample belonged to the relatively intact group, highlighting that neuropsychological assessment is needed for the precise characterization of the individual.

Neurocognitive functioning during symptomatic states and remission in bipolar disorder and schizophrenia: A comparative study

Aims Patients with bipolar disorder present milder cognitive impairment in comparison to patients with schizophrenia. Psychotic symptoms are associated with poorer cognitive functioning in both disorders. We aim to compare cognitive dysfunction between bipolar disorder and schizophrenia across symptomatic and remitted states. Methods An extensive cognitive battery was used to assess bipolar disorder patients (32 in manic episodes with psychotic features, 44 in euthymia), patients with schizophrenia (41 symptomatic, 39 remitted), and 55 healthy controls. A global cognitive factor and six neurocognitive domain factors were identified using principal component analyses. Results Global cognition components differed according to both illness and remission status; working memory differed according to remission status regardless of diagnosis; verbal fluency differed according to diagnosis regardless of remission status. An omnibus F test revealed that the remission state had a significant impact on processing speed in schizophrenia. Conclusion Our data suggest that both disorders are associated with state dependent (i.e., global cognition and working memory) and diagnosis dependent (i.e., global cognition and verbal fluency) neurocognitive dysfunctions. Processing speed was exclusively influenced by symptomatic states of schizophrenia.

Long-term Changes in Cognitive Functioning in Individuals With Psychotic Disorders: Findings From the Suffolk County Mental Health Project

IMPORTANCE

It remains uncertain whether people with psychotic disorders experience progressive cognitive decline or normal cognitive aging after first hospitalization. This information is essential for prognostication in clinical settings, deployment of cognitive remediation, and public health policy.

OBJECTIVE

To examine long-term cognitive changes in individuals with psychotic disorders and to compare age-related differences in cognitive performance between people with psychotic disorders and matched control individuals (ie, individuals who had never had psychotic disorders).

DESIGN, SETTING, AND PARTICIPANTS

The Suffolk County Mental Health Project is an inception cohort study of first-admission patients with psychosis. Cognitive functioning was assessed 2 and 20 years later. Patients were recruited from the 12 inpatient facilities of Suffolk County, New York. At year 20, the control group was recruited by random digit dialing and matched to the clinical cohort on zip code and demographics. Data were collected between September 1991 and July 2015. Analysis began January 2016.

MAIN OUTCOMES AND MEASURES

Change in cognitive functioning in 6 domains: verbal knowledge (Wechsler Adult Intelligence Scale-Revised vocabulary test), verbal declarative memory (Verbal Paired Associates test I and II), visual declarative memory (Visual Reproduction test I and II), attention and processing speed (Symbol Digit Modalities Test-written and oral; Trail Making Test [TMT]-A), abstraction-executive function (Trenerry Stroop Color Word Test; TMT-B), and verbal fluency (Controlled Oral Word Association Test).

RESULTS

A total of 705 participants were included in the analyses (mean [SD] age at year 20, 49.4 [10.1] years): 445 individuals (63.1%) had psychotic disorders (211 with schizophrenia spectrum [138 (65%) male]; 164 with affective psychoses [76 (46%) male]; 70 with other psychoses [43 (61%) male]); and 260 individuals (36.9%) in the control group (50.5 [9.0] years; 134 [51.5%] male). Cognition in individuals with a psychotic disorder declined on all but 2 tests (average decline: d = 0.31; range, 0.17-0.54; all P < .001). Cognitive declines were associated with worsening vocational functioning (Visual Reproduction test II: r = 0.20; Symbol Digit Modalities Test-written: r = 0.25; Stroop: r = 0.24; P < .009) and worsening negative symptoms (avolition: Symbol Digit Modalities Test-written: r = -0.24; TMT-A: r = -0.21; Stroop: r = -0.21; all P < .009; inexpressivity: Stroop: r = -0.22; P < .009). Compared with control individuals, people with psychotic disrders showed age-dependent deficits in verbal knowledge, fluency, and abstraction-executive function (vocabulary: β = -0.32; Controlled Oral Word Association Test: β = -0.32; TMT-B: β = 0.23; all P < .05), with the largest gap among participants 50 years or older.

CONCLUSIONS AND RELEVANCE

In individuals with psychotic disorders, most cognitive functions declined over 2 decades after first hospitalization. Observed declines were clinically significant. Some declines were larger than expected due to normal aging, suggesting that cognitive aging in some domains may be accelerated in this population. If confirmed, these findings would highlight cognition as an important target for research and treatment during later phases of psychotic illness.

A comparative meta-analysis of neurocognition in first-degree relatives of patients with schizophrenia and bipolar disorder

Objective:

Cognitive impairment is a familial and heritable aspect of major psychoses and might be a shared vulnerability marker for schizophrenia and BP. However, it is not clear whether some aspects of cognitive deficits are uniquely associated with risk for specific diagnoses.

Methods:

A novel meta-analysis of cognitive functions in first-degree relatives of probands with bipolar disorder (BP-Rel) and schizophrenia (Sch-Rel) was conducted. Current meta-analysis included 20 studies and compared cognitive functions of 1341 Sch-Rel, 939 BP-Rel and 1427 healthy controls.

Results:

Sch-Rel was associated with cognitive deficits in all domains (d = 0.20–0.58) and BP-Rel underperformed healthy controls in processing speed, verbal fluency and speed based executive function tests (d = 0.33–0.41). Sch-Rel underperformed BP-Rel in general intellectual ability, working memory, verbal memory, planning, processing speed and fluency (d = 0.24–0.42).

Conclusions:

Inefficiency in processing information and impaired processing speed might be common vulnerability factors for major psychoses. On the other hand, low performance in accuracy based tasks and deficits in general intellectual ability, verbal learning, planning and working memory might be more specifically associated with risk for schizophrenia.

A meta-analysis of neurocognition in youth with familial high risk for bipolar disorder

Objective:

Neuropsychological impairment, including deficits in social cognition is evident in subjects at genetic high-risk for psychosis. However, findings in youth at genetic risk to bipolar disorder (BP) have been suggested to be less supportive of premorbid deficits. We aimed to conduct a meta-analysis of cognitive deficits in youth with familiar risk for bipolar disorder (FHR-BD).

Methods:

A novel meta-analysis of FHR-BD (mean age 10–25), including 18 studies (786 offsprings/siblings of patients with BD and 794 healthy controls), was conducted.

Results:

Both general cognition (d = 0.29, CI = 0.15–0.44) and social cognition (d = 0.23, CI = 0–0.45) were impaired in FHR-BD. In comparison to controls, FHR-BD had significant deficits in several cognitive domains, including visual memory (d = 0.35), verbal memory (d = 0.21), processing speed (d = 0.26) and sustained attention (d = 0.36). There was no significant difference between FHR-BD and controls in planning and working memory.

Conclusions:

Cognitive deficits are evident in individuals who are at genetic high-risk for developing BD. Neurodevelopmental abnormalities are likely playing a role not only in schizophrenia but also in BD.

Neurodevelopmental pathways in bipolar disorder

Aberrations in neurodevelopmental trajectories have been implicated in the neurobiology of several mental disorders and evidence indicates a pathophysiological and genetic overlap of schizophrenia and bipolar disorder (BD). In this narrative review, we summarize findings related to developmental and perinatal factors as well as epidemiological, clinical, neuropsychological, brain imaging, postmortem brain and genomic studies that provide evidence for a putative neurodevelopmental pathogenesis and etiology of BD. Overall, aberrations in neurodevelopmental pathways have been more consistently implicated in the pathophysiology of schizophrenia compared to BD. Nevertheless, an accumulating body of evidence indicates that dysfunctional neurodevelopmental pathways may be implicated in the underlying pathophysiology of at least a subset of individuals with BD particularly those with an early age of illness onset and those exhibiting psychotic symptoms. A heuristic neurodevelopmental model for the pathophysiology of BD based on the findings of this review is proposed. Furthermore, we critically discuss clinical and research implications of this model. Finally, further research directions for this emerging field are provided.

Neurocognition in young offspring of individuals with bipolar disorder: The role of co-existing familial and clinical high-risk for bipolar disorder

Bipolar disorder (BD) is associated with cognitive dysfunction which has also been reported in offspring of individuals with BD (BDoff). However, it remains unclear whether cognitive underperformance in BDoff is associated with the presence of history of subclinical syndromes associated with risk for BD. To address this knowledge gap we assessed executive function, visual and verbal memory, working memory, processing speed and verbal fluency in 21 offspring with clinical high risk (CHR; BDoff+CHR), 54 offspring without CHR (BDoff-non-CHR), and 50 healthy individuals without familial risk of BD. BDoff underperformed compared to controls in most cognitive tasks. There was no significant neurocognitive difference between BDoff+CHR and BDoff-non-CHR except in the fluency/central executive domain (Cohen's d = 0.60, p = 0.03). Our results suggest that cognitive dysfunction in multiple domains is associated with familial predisposition to BD regardless of CHR status. On the other hand, abnormalities in central executive processes might be more pronounced in BDoff+CHR than BDoff-non-CHR. Further longitudinal studies investigating cognitive trajectory of BDoff and its interaction with the emergence of subclinical syndromes are needed to fully characterize the relationship between cognition and mood dysregulation in BD.

Neurocognitive heterogeneity in young offspring of patients with bipolar disorder: The effect of putative clinical stages

BACKGROUND

Bipolar disorder (BD) is associated with significant cognitive heterogeneity. In recent years, a number of studies have investigated cognitive subgroups in BD using data-driven methods and found that BD includes several subgroups including a severely impaired and a neurocognitively intact cluster. Studies in offspring of BD (BDoff) are particularly important to establish the timing of emergence of cognitive subgroups but studies investigating cognitive heterogeneity in BDoff are lacking. Our aim was to investigate cognitive heterogeneity in BDoff and the relationship between cognitive heterogeneity and putative clinical stages of BD.

METHODS

Seventy-one euthymic BDoff and 50 healthy controls were assessed using clinical measures and a battery of neuropsychological tests. Neurocognitive subgroups were investigated using latent class analysis.

RESULTS

Three neurocognitive subgroups, including a severe impairment group, a good performance cluster, and a subgroup characterized by intermediate/selective impairment was found. Both severe and intermediate level impairment subgroups underperformed healthy controls in processing speed, verbal fluency, visual memory and working memory. Deficits in verbal memory and executive functions were only evident in severe impairment subgroup. The putative stage of the illness had no significant effect on cognitive clustering of BDoff. Trait impulsivity scores were significantly increased in severe and intermediate impairment clusters but not in the cognitively good functioning subgroup of BDoff.

LIMITATIONS

The cross-sectional nature of the study was the main consideration.

CONCLUSION

These results suggest that cognitive heterogeneity is premorbid characteristic of BD and cognitive subgroups of BDoff emerge prior to the onset of illness and prodromal symptoms.

A symptom-based continuum of psychosis explains cognitive and real-world functional deficits better than traditional diagnoses

BACKGROUND

Patients with psychotic spectrum disorders share overlapping clinical/biological features, making it often difficult to separate them into a discrete nosology (i.e., Diagnostic and Statistical Manual of Mental Disorders [DSM]).

METHODS

The current study investigated whether a continuum classification scheme based on symptom burden would improve conceptualizations for cognitive and real-world dysfunction relative to traditional DSM nosology. Two independent samples (New Mexico [NM] and Bipolar and Schizophrenia Network on Intermediate Phenotypes [B-SNIP]) of patients with schizophrenia (NM: N = 93; B-SNIP: N = 236), bipolar disorder Type I (NM: N = 42; B-SNIP: N = 195) or schizoaffective disorder (NM: N = 15; B-SNIP: N = 148) and matched healthy controls (NM: N = 64; B-SNIP: N = 717) were examined. Linear regressions examined how variance differed as a function of classification scheme (DSM diagnosis, negative and positive symptom burden, or a three-cluster solution based on symptom burden).

RESULTS

Symptom-based classification schemes (continuous and clustered) accounted for a significantly larger portion of captured variance of real-world functioning relative to DSM diagnoses across both samples. The symptom-based classification schemes accounted for large percentages of variance for general cognitive ability and cognitive domains in the NM sample. However, in the B-SNIP sample, symptom-based classification schemes accounted for roughly equivalent variance as DSM diagnoses. A potential mediating variable across samples was the strength of the relationship between negative symptoms and impaired cognition.

CONCLUSIONS

Current results support suggestions that a continuum perspective of psychopathology may be more powerful for explaining real-world functioning than the DSM diagnostic nosology, whereas results for cognitive dysfunction were sample dependent.

Characteristics of Cognitive in Children with Learning Difficulties

In order to explore the relationship between cognitive function in children with learning difficulties and social environment, this study uses the Wechsler Intelligence Scale and the self-made general environment questionnaire to investigate 185 children with learning difficulties and compares them with 185 normal children, and gives attention test to 50 children with learning difficulties. The results show that family environment has a certain influence on the children with learning difficulties, they have a significantly lower verbal intelligence quotient (VIQ), performance intelligence quotient (PIQ) and full scale intelligence quotient (FIQ), and the separation of VIQ and P IQ is common among them. As the children with learning difficulties grow older, their ability for abstract generalization tends to decline, which may be a characteristic of their intelligence development. This study aims to compare the functional differences in cortical regions between children with learning difficulties and children without from the perspective of cognitive neuropsychology, so as to provide effective assistance for children with learning difficulties.

Neurococognitive and neuroimaging correlates of obesity and components of metabolic syndrome in bipolar disorder: a systematic review

BACKGROUND

Individuals with bipolar disorder (BD) have a higher prevalence of obesity and metabolic syndrome (MetS) compared with the general population. Obesity and MetS are associated with cognitive deficits and brain imaging abnormalities in the general population. Obesity and components of MetS might potentially associate with neuroimaging and neurocognitive findings in BD.

METHODS

A literature search of studies investigating the association between obesity (and other components of MetS) and neurocognitive and neuroimaging findings in BD was conducted. In addition to a systematic review, a random-effects meta-analysis was conducted when sufficient data were available.

RESULTS

Twenty-three studies were included in the current systematic review. Overweight/obese patients were significantly associated with impaired neurocognition compared normal weight individuals with BD (d = 0.37). The most robust association between obesity and cognitive deficits in BD was observed in the cognitive subdomain of executive functions (d = 0.61). There was also evidence for a significant relationship between cognitive impairment in BD and other components of MetS including hypertension, dyslipidemia, and diabetes. Overweight/obese individuals with BD had more pronounced brain imaging abnormalities than normal weight individuals with BD.

CONCLUSIONS

Obesity and related cardiovascular risk factors significantly are associated with more severe cognitive and brain imaging abnormalities in BD. Medical co-morbidities can potentially contribute to functional decline observed in some patients throughout the course of BD.

Behavioral, affective, and cognitive alterations induced by individual and combined environmental stressors in rats

OBJECTIVE

To evaluate whether exposing rats to individual or combined environmental stressors triggers endophenotypes related to mood and anxiety disorders, and whether this effect depends on the nature of the behavior (i.e., innate or learned).

METHODS

We conducted a three-phase experimental protocol. In phase I (baseline), animals subjected to mixed schedule of reinforcement were trained to press a lever with a fixed interval of 1 minute and a limited hold of 3 seconds. On the last day of phase I, an open-field test was performed and the animals were divided into four experimental groups (n=8/group). In phase II (repeated stress), each group was exposed to either hot air blast (HAB), paradoxical sleep deprivation (PSD) or both (HAB+PSD group) on alternate days over a 10-day period. Control group animals were not exposed to stressors. In phase III (post-stress evaluation), behavior was analyzed on the first (short-term effects), third (mid-term effects), and fifth (long-term effects) days after repeated stress.

RESULTS

The PSD group presented operant hyperactivity, the HAB group presented spontaneous hypoactivity and anxiety, and the HAB+PSD group presented spontaneous hyperactivity, operant hypoactivity, impulsivity, loss of interest, and cognitive impairment.

CONCLUSION

A combination of environmental stressors (HAB and PSD) may induce endophenotypes related to bipolar disorder.

Neurological soft signs in bipolar disorder in comparison to healthy controls and schizophrenia: A meta-analysis

Neurological soft signs (NSS) are subtle deficits in motor coordination, sensory integration, and sequencing of complex motor acts. Increased NSS is a well-established feature of patients with schizophrenia but a relatively smaller number of studies have investigated NSS in bipolar disorder (BD). Some authors but not others suggested that NSS can distinguish schizophrenia from BD. We conducted a meta-analysis of 18 studies to quantitatively review NSS in BD in comparison to schizophrenia and healthy controls. The current meta-analysis compared NSS scores of 725 BD patients and 634 healthy controls, and 391 BD and 471 schizophrenia patients. Patients with BD had significantly higher NSS scores (d = 1.14, CI = 0.89-1.44) than healthy controls and increased scores in BD was evident in all aspects of NSS (d = 0.88-0.99). BD was associated with a less severe increase in NSS compared to schizophrenia, however, between-group difference was modest (d = 0.42, CI = 0.18-0.65). The results of this meta-analysis demonstrated that BD is characterized by a robust increase in NSS which is only moderately less severe than schizophrenia. Increased NSS is a common feature of both disorders.

Affective versus non-affective first episode psychoses: A longitudinal study

OBJECTIVE

This study aimed to assess (1) whether there were clinical, neuropsychological and functional differences between and within affective and non-affective psychoses at baseline and two years-follow-up and (2) to explore clinical and neuropsychological predictors of psychosocial functioning in the whole sample.

METHOD

This is a subanalysis from a multicentre, naturalistic, longitudinal prospective study ('Phenotype-genotype and environmental interaction. Application of a predictive model in first psychotic episodes'). The sample consisted of 192 patients with a first psychotic episode (FEP): 142 with non-affective psychoses and 50 with affective psychoses. Student t-tests, paired t-tests, Pearson correlations, ANOVAs and regression analyses were performed.

RESULTS

At baseline, the groups differed in perseverative errors (WCST), Premorbid Adjustment Scale (PAS), family history of psychiatric disorder, negative (PANSS) and manic symptoms (YMRS). At two years follow-up, the groups differed in all the PANSS subscales and in depressive symptoms assessed by the MADRS. When the whole sample was considered, the regression model which best explained the estimated variance in functioning at follow-up (41%) was composed by PANSS total score and verbal fluency assessed by the FAS (COWAT).

CONCLUSIONS

We found clinical and neurocognitive differences at baseline which decreased in the follow-up. Reduced performances at baseline in executive functions in combination with symptom severity (PANSS) were predictors of FEP patients' poor functional outcome.

Association Between Muscular Strength and Cognition in People With Major Depression or Bipolar Disorder and Healthy Controls

IMPORTANCE

Objective physical fitness measures, such as handgrip strength, are associated with physical, mental, and cognitive outcomes in the general population. Although people with mental illness experience reduced physical fitness and cognitive impairment, the association between muscular strength and cognition has not been examined to date.

OBJECTIVE

To determine associations between maximal handgrip strength and cognitive performance in people with major depression or bipolar disorder and in healthy controls.

DESIGN, SETTING, AND PARTICIPANTS

In a multicenter, population-based study conducted between February 13, 2005, and October 1, 2010, in the United Kingdom, cross-sectional analysis was conducted of baseline data from 110 067 participants in the UK Biobank. Data analysis was performed between August 3 and August 18, 2017. Invitations were mailed to approximately 9.2 million UK homes, recruiting 502 664 adults, all aged 37 to 73 years. Clinically validated measures were used to identify individuals with major recurrent depression (moderate or severe) or bipolar disorder (type I or type II) and healthy controls (those with no indication of present or previous mood disorders).

MAIN OUTCOMES AND MEASURES

Handgrip dynamometry was used to measure muscular function. Cognitive functioning was assessed using computerized tasks of reaction time, visual memory, number memory, reasoning, and prospective memory. Generalized linear mixed models assessed the association between handgrip strength and cognitive performance, controlling for age, educational level, sex, body weight, and geographic region.

RESULTS

Of the 110 067 participants, analyses included 22 699 individuals with major depression (mean [95% range] age, 55.5 [41-68] years; 7936 [35.0%] men), 1475 with bipolar disorder (age, 54.4 [41-68] years; 748 [50.7%] men), and 85 893 healthy controls (age, 53.7 [41-69] years; 43 000 [50.0%] men). In those with major depression, significant positive associations (P < .001) between maximal handgrip strength and improved performance on all 5 cognitive tasks were found, including visual memory (coefficient, -0.146; SE, 0.014), reaction time (coefficient, -0.036; SE, 0.002), reasoning (coefficient, 0.213; SE, 0.02), number memory (coefficient, 0.160; SE, 0.023), and prospective memory (coefficient, 0.341; SE, 0.024). Similar results were found in healthy controls. Among participants with bipolar disorder, handgrip strength was positively associated with improved visual memory (coefficient, -0.129; SE, 0.052; P = .01), reaction time (coefficient, -0.047; SE, 0.007; P < .001), prospective memory (coefficient, 0.262; SE, 0.088; P = .003), and reasoning (coefficient, 0.354; SE, 0.08; P < .001).

CONCLUSIONS AND RELEVANCE

Grip strength may provide a useful indicator of cognitive impairment in people with major depression and bipolar disorder. Future research should investigate causality, assess the functional implications of handgrip strength in psychiatric populations, and examine how interventions to improve muscular fitness affect neurocognitive status and socio-occupational functioning.

Critical reappraisal of mechanistic links of copy number variants to dimensional constructs of neuropsychiatric disorders in mouse models

Copy number variants are deletions and duplications of a few thousand to million base pairs and are associated with extraordinarily high levels of autism spectrum disorder, schizophrenia, intellectual disability, or attention-deficit hyperactivity disorder. The unprecedented levels of robust and reproducible penetrance of copy number variants make them one of the most promising and reliable entry points to delve into the mechanistic bases of many mental disorders. However, the precise mechanistic bases of these associations still remain elusive in humans due to the many genes encoded in each copy number variant and the diverse associated phenotypic features. Genetically engineered mice have provided a technical means to ascertain precise genetic mechanisms of association between copy number variants and dimensional aspects of mental illnesses. Molecular, cellular, and neuronal phenotypes can be detected as potential mechanistic substrates for various behavioral constructs of mental illnesses. However, mouse models come with many technical pitfalls. Genetic background is not well controlled in many mouse models, leading to rather obvious interpretative issues. Dose alterations of many copy number variants and single genes within copy number variants result in some molecular, cellular, and neuronal phenotypes without a behavioral phenotype or with a behavioral phenotype opposite to what is seen in humans. In this review, I discuss technical and interpretative pitfalls of mouse models of copy number variants and highlight well-controlled studies to suggest potential neuronal mechanisms of dimensional aspects of mental illnesses. Mouse models of copy number variants represent toeholds to achieve a better understanding of the mechanistic bases of dimensions of neuropsychiatric disorders and thus for development of mechanism-based therapeutic options in humans.

Neurocognitive features in clinical subgroups of bipolar disorder: A meta-analysis

OBJECTIVE

There is a significant cognitive heterogeneity in bipolar disorder (BD). The aim of this systematic review was to examine the potential distinctive neuropsychological of features of clinical subgroups of BD. A literature search investigating cognitive differences between potential subtypes of BD was conducted.

METHODS

It was possible to conduct a meta-analysis of studies investigating the relationship between cognitive deficits and subgroups of DSM-IV BD (type I (BD-I) and type II (BD-II)), subgroups based on history of psychosis (PBD and NPBD). The cognitive domains investigated in this meta-analysis included verbal memory, visual memory, processing speed, executive functions speed (EF-speed), EF-accuracy, attention, working memory, social cognition. Current meta-analysis included 48 reports and compared cognitive performances of 1211 BD-I and 836 BD-II patients. It also compared cognitive functioning in 1017 PBD and 744 NPBD patients.

RESULTS

Both history of psychosis (d = 0.19) and BD-I (d = 0.17) diagnosis were associated with modestly more pronounced global cognitive impairment. In specific domains, BD-I significantly underperformed BD-II in verbal memory, processing speed, EF-speed, EF-accuracy (d = 0.15-0.26). PBD was associated with significantly impaired cognition compared to NPBD in verbal memory, processing speed, EF-speed, EF-accuracy, working memory and social cognition (d = 0.12-0.28).

CONCLUSION

In BD, history of psychosis and full-manic episode are modestly associated with increased cognitive deficits. Neurocognitive differences between clinical subtypes of BD are quite subtle and are not distinctive. Furthermore, other factors reflecting differences in illness severity can explain observed between-group differences. Most of the cognitive heterogeneity in BD cannot be explained by proposed subtypes of BD.

Cognitive functioning in first episode bipolar I disorder patients with and without history of psychosis

BACKGROUND

Psychosis in bipolar I disorder (BDI) has been associated with increased cognitive dysfunction, which may relate to poorer functional outcomes. However, it is not known whether cognition differs between BDI patients with (BDP+) or without (BDP-) history of psychosis early in the disease course, or if it is impacted by the presence of mood congruent (MCP) versus incongruent (MIC) psychotic features. We compare cognition between these groups in BDI patients recently recovered from first episode of mania.

METHODS

Attention, verbal learning/memory, processing speed and executive functioning were compared between: 1) all BDI patients (n = 73) and healthy controls (HC, n = 45), 2) BDP+ (n = 60) and BDP- (n = 13) patients and 3) MCP (n = 27) and MIC (n = 33) patients. Post-hoc analyses compared all patient groups with HC.

RESULTS

While BDI patients performed worse than HC in all domains, there were no significant differences between BDP+ and BDP-, or MCP and MIC, patients. However, BDP+ and MIC groups demonstrated different patterns of impairment compared to HC then did BDP- or MCP. Executive functioning and cognitive flexibility in particular appeared to be a deficit area in BDP+ patients.

LIMITATIONS

This study may have been underpowered to detect differences in direct comparison between BDP+ and BDP- patients.

CONCLUSION

While replication in larger samples is required, these results suggest that subtle cognitive differences between BDP+ and BDP-, and between MIC and MCP, patients may be present shortly after disease onset. These patient subsets may therefore be of interest in examining early intensive strategies to preserve cognition.

Staging, Neurocognition and Social Functioning in Bipolar Disorder

Introduction: Bipolar disorder (BD) is associated with significant neurocognitive and functional impairment, which may progress across stages. The 'latent stage' of BD remains understudied. This cross-sectional study assessed staging, neurocognition and social functioning among BD patients and their healthy siblings. Methods: Four groups were included: euthymic type I BD patients in the early (n = 25) and late (n = 23) stages, their healthy siblings (latent stage; n = 23) and healthy controls (n = 21). All 92 subjects underwent a comprehensive neuropsychological battery of processing speed, verbal learning/memory, visual memory, working memory, verbal fluency, executive cognition, and motor speed. Social functioning was assessed using the FAST scale. Results: Siblings' social functioning was identical to that of controls, and significantly better than both early- (p < 0.005) and late- (p < 0.001) stage patients. Although all patients were strictly euthymic, those at late stages had a significantly worse social functioning than early-stage patients (p < 0.001). Compared to controls, increasingly greater neurocognitive dysfunction was observed across stages of BD (F = 1.59; p = 0.005). Healthy siblings' performance lied between those of controls and patients, with deficits in tasks of processing speed, executive attention, verbal memory/learning, and visual memory. Both early- and late-stage patients had a more severe and widespread dysfunction than siblings, with no significant differences between them. Conclusions: Genetic vulnerability to BD-I seems to be associated with neurocognitive impairments, whereas social dysfunction would be the result of the clinical phenotype. Staging models of BD should take into account these divergent findings in the latent stage.

Meta-analysis of longitudinal studies of cognition in bipolar disorder: comparison with healthy controls and schizophrenia

BACKGROUND

Bipolar disorder (BP) is associated with significant cognitive impairment. Recent evidence suggests that cognitive deficits are already evident after first-episode mania. However, it is not clear whether BP is associated with further decline in cognitive functions in individuals with established illness. Aim of this meta-analytic review was to examine longitudinal neurocognitive changes in BP and to compare trajectory of cognitive deficits in BP with schizophrenia and healthy controls.

METHODS

Electronic databases were searched for the studies published between January 1987 and November 2016. In total 22 reports were included in the current meta-analysis. The main analysis assessed the longitudinal change in cognition in 643 patients with BP. Further analyses were conducted in studies investigating cognitive changes in BP along with healthy controls (459 BP and 367 healthy controls) and schizophrenia (172 BP and 168 schizophrenia).

RESULTS

There was no cognitive decline overtime neither in short-term (mean duration = 1.5 years) nor in long-term (mean duration = 5.5 years) follow-up studies in BP. In contrast, there was evidence for modest improvements in task performance in memory and working memory at follow-up. The trajectory of cognitive functioning in BP was not significantly different from changes in schizophrenia and healthy controls.

CONCLUSIONS

Together with the findings in early BP and individuals at genetic risk for BP, current findings suggest that neurodevelopmental factors might play a significant role in cognitive deficits in BP and do not support the notion of progressive cognitive decline in most patients with BP.

Social cognition in first-degree relatives of patients with bipolar disorder: A meta-analysis

Cognitive impairment is evident euthymic patients with bipolar disorder (BP) and in their first-degree relatives (BP-Rel). Increasing evidence suggests that BP is also associated with social cognitive impairment. It is important to establish whether social cognitive impairment is also evident in BP-Rel. A novel meta-analysis of theory of mind (ToM) and facial emotion recognition in BP-Rel including 16 studies (728 first-degree relatives of patients with BP and 865 healthy controls) was conducted. ToM (d=0.34, CI=0.16-0.52) was significantly impaired in BP-Rel. The effect size for the difference between BP-Rel and healthy controls was smaller for facial emotion recognition (d=0.17, CI=0.16-0.29) and could be nonsignificant after the effect of publication bias was taken into account. First-degree relatives of patients with BP underperform healthy subjects in social cognitive abilities, particularly in ToM. However, the effect size for between-group difference is small. ToM impairment might be a vulnerability marker of BP.

Influences of patient informed cognitive complaints on activities of daily living in patients with bipolar disorder. An exploratory cross-sectional study

Many patients with bipolar disorder (BD) experience debilitating cognitive deficits, with risk of impaired occupational and psychosocial functioning. However, knowledge of how these deficits impact the patients' ability to perform Activities of Daily Living (ADL), tasks related to self-care and domestic life is limited. We explored the relation between impaired cognitive function and the ability to perform ADL in patients with BD. A total of 42 outpatients (mean age 36 years (range 19.0-58.0 years), 69% women) with BD in remission and with subjective cognitive complaints (≥ 13 on the Cognitive Complaints in Bipolar Disorder Rating Assessment questionnaire (COBRA)) were included. Objective neurocognitive function was evaluated with a short comprehensive cognitive test battery and ADL ability was evaluated with the performance-based Assessment of Motor and Process Skills (AMPS) in the homes of the patients. Our findings indicate that low processing speed correlated with decreased ADL ability, and processing speed as measured by the cognitive test battery thus seems to be significantly related to patients' ability to live independently in the community. Overall, adding a performance based test to assess ADL ability in patients with BD home-surroundings seems to provide new insights regarding the effect of cognitive impairment in patients with BD.

Educational achievement in psychiatric patients and their siblings: a register-based study in 30 000 individuals in The Netherlands

BACKGROUND

Poor educational achievement is associated with a range of psychiatric disorders. Several studies suggest that this underperformance is due to cognitive deficits that commence before disease onset and reflect a genetic risk for this disorder. However, the specificity and the familial contribution of this cognitive deficit are not clear. We analysed lifetime educational achievement of psychiatric patients diagnosed with schizophrenia, bipolar or depressive disorder and their unaffected siblings.

METHOD

In a register-based case-control study, 1561 patients with schizophrenia, 813 patients with bipolar disorder, 8112 patients with depression, and their siblings were each matched with eight population controls. Patients, siblings and controls were compared on the highest educational stream they completed.

RESULTS

Lower educational achievement was present in schizophrenia patients from primary school onwards [completing primary school: odds ratio (OR) 0.69; completing secondary school: OR 0.69; completing academic education: OR 0.46], compared to patients with bipolar disorder or depression. Siblings of schizophrenia, bipolar or depressed patients showed no underachievement at primary or secondary school, but siblings of schizophrenia patients as well as siblings of depressed patients were less successful in their educational achievement after secondary school (completing academic education, schizophrenia siblings: OR 0.90; depressive disorder siblings: OR 0.91).

CONCLUSIONS

Educational underachievement from primary school onwards is specifically related to schizophrenia and not to bipolar disorder or depression. Moreover, it appears to be a harbinger of the illness, since it is not found in their siblings. These results add to evidence that early cognitive deficits are a distinct feature of the schizophrenia phenotype.

Systematic assessment of environmental risk factors for bipolar disorder: an umbrella review of systematic reviews and meta-analyses

OBJECTIVES

The pathophysiology of bipolar disorder is likely to involve both genetic and environmental risk factors. In our study, we aimed to perform a systematic search of environmental risk factors for BD. In addition, we assessed possible hints of bias in this literature, and identified risk factors supported by high epidemiological credibility.

METHODS

We searched the Pubmed/MEDLINE, EMBASE and PsycInfo databases up to 7 October 2016 to identify systematic reviews and meta-analyses of observational studies that assessed associations between putative environmental risk factors and BD. For each meta-analysis, we estimated its summary effect size by means of both random- and fixed-effects models, 95% confidence intervals (CIs), the 95% prediction interval, and heterogeneity. Evidence of small-study effects and excess of significance bias was also assessed.

RESULTS

Sixteen publications met the inclusion criteria (seven meta-analyses and nine qualitative systematic reviews). Fifty-one unique environmental risk factors for BD were evaluated. Six meta-analyses investigated associations with a risk factor for BD. Only irritable bowel syndrome (IBS) emerged as a risk factor for BD supported by convincing evidence (k=6; odds ratio [OR]=2.48; 95% CI=2.35-2.61; P<.001), and childhood adversity was supported by highly suggestive evidence. Asthma and obesity were risk factors for BD supported by suggestive evidence, and seropositivity to Toxoplasma gondii and a history of head injury were supported by weak evidence.

CONCLUSIONS

Notwithstanding that several environmental risk factors for BD were identified, few meta-analyses of observational studies were available. Therefore, further well-designed and adequately powered studies are necessary to map the environmental risk factors for BD.