Neuropsychological and social cognitive function in young people at genetic risk of bipolar disorder

Cortical alterations in relatives of patients with bipolar disorder: A review of magnetic resonance imaging studies

INTRODUCTION

Bipolar disorder (BD) is a severe mental disorder characterized by high heritability rates. Widespread brain cortical alterations have been reported in BD patients, mostly involving the frontal, temporal and parietal regions. Importantly, also unaffected relatives of BD patients (BD-RELs) present abnormalities in cortical measures, which are not influenced by disease-related factors, such as medication use and illness duration. Here, we collected all available evidence on cortical measures in BD-RELs to further our knowledge on the potential cortical alterations associated with the vulnerability and the resilience to BD.

METHODS

A search on PubMed, Web of Science and Scopus was performed to identify neuroimaging studies exploring cortical alterations in BD-RELs, including cortical thickness (CT), surface area (SA), gyrification (GI) and cortical complexity. Eleven studies were included. Of these, five assessed CT, five examined CT and SA and one explored CT, SA and GI.

RESULTS

Overall, a heterogeneous pattern of cortical alterations emerged. The areas more consistently linked with genetic liability for BD were the prefrontal and sensorimotor regions. Mixed evidence was reported in the temporal and cingulate areas.

LIMITATIONS

The small sample size and the heterogeneity in terms of methodologies and the characteristics of the participants limit the generalizability of our results.

CONCLUSIONS

Our findings suggest that the genetic liability for BD is related to reduced CT in the prefrontal cortex, which might be a marker of risk for BD, and increased CT within the sensorimotor cortex, which could represent a marker of resilience.

Functional Alterations in Patients with Bipolar Disorder and Their Unaffected First-Degree Relatives: Insight from Genetic, Epidemiological, and Neuroimaging Data

Bipolar disorder (BD) profoundly affects cognitive and psychosocial functioning, leading to a significant illness burden on patients and their families. Genetic factors are predominant in the onset of bipolar disorder and functional impairments. This disorder exhibits a strong family aggregation, with heritability estimates reaching up to 80%. Individuals with BD often experience impaired functioning, especially in significant areas such as physical performance, sleep, cognition, interpersonal interactions, socioeconomic status, family and marital relationships, work and school performance, well-being, and life expectancy. However, patients with different subtypes exhibit significant heterogeneity in social functioning, cognition, and creativity levels. There are notable differences in psychosocial and cognitive function in their unaffected first-degree relatives (UFR) who do not suffer but may carry susceptibility genes compared to healthy control (HC) without a family history. The observations indicate common genetic structures between BD patients and their UFR, which results in varying degrees of functional abnormalities. Therefore, this article mainly provides evidence on cognition, creativity, and psychosocial functioning in patients with BD and their UFR to provide a more comprehensive understanding of this critical topic in the field of BD. By integrating various findings, including clinical data and neuroimaging studies, our article aims to provide insights and valuable information for a deeper exploration of the pathogenesis of BD and the development of more targeted therapeutic strategies in the future.

Mapping the scientific research on bipolar disorder: A scientometric study of hotspots, bursts, and trends

Bipolar disorder (BD) is a severe psychiatric illness with an increasing prevalence worldwide. Although the pathological mechanism of and pharmacological interventions for BD have been extensively investigated in preclinical and clinical studies, a scientometric analysis of the developmental trends, interdisciplinary frontiers, and research hotspots in this field has not yet been conducted. Therefore, we performed a comprehensive scientometric review of 55,358 published studies on BD over the past two decades (2002-2021) to identify the most frequently used keywords and explore research hotspots and trajectories. The present findings revealed the main distribution, knowledge structure, topic evolution, and emerging topics of BD research. Analysing the risk factors, pathogenesis, key brain regions, comorbid conditions, and treatment strategies for BD contributed to understanding of the aetiology, progression, and treatment of this disorder. These findings provided substantial support for continued research in this area.

Emotional cognition subgroups in unaffected first-degree relatives of patients with mood disorders

BACKGROUND

Patients with major depressive disorder (MDD) or bipolar disorder (BD) exhibit difficulties with emotional cognition even during remission. There is evidence for aberrant emotional cognition in unaffected relatives of patients with these mood disorders, but studies are conflicting. We aimed to investigate whether emotional cognition in unaffected first-degree relatives of patients with mood disorders is characterised by heterogeneity using a data-driven approach.

METHODS

Data from 94 unaffected relatives (33 of MDD patients; 61 of BD patients) and 203 healthy controls were pooled from two cohort studies. Emotional cognition was assessed with the Social Scenarios Test, Facial Expression Recognition Test and Faces Dot-Probe Test. Hierarchical cluster analysis was conducted using emotional cognition data from the 94 unaffected relatives. The resulting emotional cognition clusters and controls were compared for emotional and non-emotional cognition, demographic characteristics and functioning.

RESULTS

Two distinct clusters of unaffected relatives were identified: a relatively 'emotionally preserved' cluster (55%; 40% relatives of MDD probands) and an 'emotionally blunted' cluster (45%; 29% relatives of MDD probands). 'Emotionally blunted' relatives presented with poorer neurocognitive performance (global cognition p = 0.010), heightened subsyndromal mania symptoms (p = 0.004), lower years of education (p = 0.004) and difficulties with interpersonal functioning (p = 0.005) than controls, whereas 'emotionally preserved' relatives were comparable to controls on these measures.

CONCLUSIONS

Our findings show discrete emotional cognition profiles that occur across healthy first-degree relatives of patients with MDD and BD. These emotional cognition clusters may provide insight into emotional cognitive markers of genetically distinct subgroups of individuals at familial risk of mood disorders.

Association of neurocognitive function with psychiatric hospitalization and socio-demographic conditions in individuals with bipolar and major depressive disorders

Background

Neurocognitive impairments are associated with poor clinical and employment outcomes in individuals with affective disorders. However, little is known about their associations with long-term clinical outcomes such as psychiatric hospitalizations, and with socio-demographic indicators other than employment. In the largest longitudinal study of neurocognition in affective disorders to date, we investigate the role of neurocognitive impairments on psychiatric hospitalizations and socio-demographic conditions.

Methods

The study included 518 individuals with bipolar or major depressive disorder. Neurocognitive assessments covered executive function and verbal memory domains. Longitudinal data on psychiatric hospitalization and socio-demographic conditions (employment, cohabitation, and marital status) for up to 11 years were obtained using National population-based registers. The primary and secondary outcomes were psychiatric hospitalizations (n = 398) and worsening of socio-demographic conditions (n = 518), in the follow-up period since study inclusion, respectively. Cox regression models were used to examine the association of neurocognition with future psychiatric hospitalizations and the worsening of socio-demographic conditions.

Findings

Clinically significant impairment in verbal memory (z-score ≤ -1; defined by the ISBD Cognition Task Force), but not in executive function, was associated with a higher risk of future hospitalization, when adjusted for age, sex, hospitalization in the year preceding inclusion, depression severity, diagnosis, and type of clinical trial (HR = 1.84, 95% CI:1.05-3.25, p = 0.034; n = 398). The results remained significant even after accounting for illness duration. Neurocognitive impairments were not associated with the worsening of socio-demographic conditions (p ≥ 0.17; n = 518).

Interpretation

Promoting neurocognitive function, especially verbal memory, may mitigate the risk of future psychiatric hospitalization in individuals with affective disorders.

Funding

Lundbeckfonden (R279-2018-1145).

The inferior frontal gyrus and familial risk for bipolar disorder

Bipolar disorder (BD) is a familial disorder with high heritability. Genetic factors have been linked to the pathogenesis of BD. Relatives of probands with BD who are at familial risk can exhibit brain abnormalities prior to illness onset. Given its involvement in prefrontal cognitive control and in frontolimbic circuitry that regulates emotional reactivity, the inferior frontal gyrus (IFG) has been a focus of research in studies of BD-related pathology and BD-risk mechanism. In this review, we discuss multimodal neuroimaging findings of the IFG based on studies comparing at-risk relatives and low-risk controls. Review of these studies in at-risk cases suggests the presence of both risk and resilience markers related to the IFG. At-risk individuals exhibited larger gray matter volume and increased functional activities in IFG compared with low-risk controls, which might result from an adaptive brain compensation to support emotion regulation as an aspect of psychological resilience. Functional connectivity between IFG and downstream limbic or striatal areas was typically decreased in at-risk individuals relative to controls, which could contribute to risk-related problems of cognitive and emotional control. Large-scale and longitudinal investigations on at-risk individuals will further elucidate the role of IFG and other brain regions in relation to familial risk for BD, and together guide identification of at-risk individuals for primary prevention.

Evaluating cognitive function in unaffected relatives of individuals with bipolar disorders: A meta-analysis

BACKGROUND

Available studies have evaluated cognition in the unaffected relatives of bipolar disorder patients; however, to our knowledge, there has been no quantitative analysis evaluating the foregoing association. Herein, this meta-analysis aims to provide a quantitative synthesis of the extant literature reporting on the association between performance in cognitive domains (i.e., executive function, attention, learning and memory or global cognition) amongst unaffected individuals of probands with bipolar disorders.

METHODS

Online databases (i.e., PubMed, PsycINFO) and Google Scholar were searched from inception to 20 September 2021. Studies with unaffected, first-degree relatives of individuals with DSM-IV or DSM-5 defined bipolar disorders were included. The risk of bias was assessed using the ROBINS-1 tool, and the quality of the sources was evaluated using GRADE criteria. The results of the studies were quantitatively synthesized using Cohen's d effect sizes via a random-effects meta-analytic approach on JASP.

RESULTS

A total of 15 studies were included in the final review. Overall, results indicate that cognitive performance across all domains is moderately impaired in unaffected relatives of individuals with bipolar disorders (d = 0.488). Sub-analysis suggests there is a higher level of impairment in executive functioning (d = 0.612).

DISCUSSION

The identification of cognitive deficits in unaffected relatives of probands with bipolar disorders indicates that cognitive impairment is endophenotypic and a core disturbance in persons with bipolar disorders; future studies should endeavour to target cognition as a potential pre-emptive and prevention strategy of bipolar disorders.

Strategies and foundations for scientific discovery in longitudinal studies of bipolar disorder

Bipolar disorder (BD) is a complex and dynamic condition with a typical onset in late adolescence or early adulthood followed by an episodic course with intervening periods of subthreshold symptoms or euthymia. It is complicated by the accumulation of comorbid medical and psychiatric disorders. The etiology of BD remains unknown and no reliable biological markers have yet been identified. This is likely due to lack of comprehensive ontological framework and, most importantly, the fact that most studies have been based on small nonrepresentative clinical samples with cross-sectional designs. We propose to establish large, global longitudinal cohorts of BD studied consistently in a multidimensional and multidisciplinary manner to determine etiology and help improve treatment. Herein we propose collection of a broad range of data that reflect the heterogenic phenotypic manifestations of BD that include dimensional and categorical measures of mood, neurocognitive, personality, behavior, sleep and circadian, life-story, and outcomes domains. In combination with genetic and biological information such an approach promotes the integrating and harmonizing of data within and across current ontology systems while supporting a paradigm shift that will facilitate discovery and become the basis for novel hypotheses.

Social cue recognition and attributional bias in remitted bipolar disorder: Impact on social functioning

The role of social cue recognition and attributional bias on social functioning has been sparsely studied in remitted bipolar disorder (BD). In view of this, we evaluated thirty subjects with BD (without a history of psychotic symptoms) who were in remission and thirty age and, gender-matched healthy controls for social cue recognition [using SoCueReTI (Social Cue Recognition Test- Indian Setting)], and attributional bias (using an Attributional style questionnaire). Social functioning was assessed in subjects with BD using the Functional assessment short test (FAST) - Interpersonal relationships. Subjects with BD had significant deficits in recognizing social cues in low-intensity and high-intensity vignettes when compared to healthy controls. Deficits in recognizing social cues in low-intensity vignettes were significantly correlated with the FAST scores, even after controlling for the number of episodes and duration of illness. Further replication studies are needed to ascertain the association between social cue recognition deficits and social functioning in BD.

Facial emotion recognition and its association with quality of life and socio-occupational functioning in patients with bipolar disorder and their first-degree relatives

INTRODUCTION

Facial emotion recognition deficits (FERD) are common even in the remitted phase of bipolar disorder (BD). Research regarding FERD in first-degree relatives is inconclusive. This study aimed to assess the facial emotion recognition in remitted patients of bipolar disorder and first-degree relatives(FDR) in comparison with healthy controls. Correlation between FERD and quality of life and socio-occupational functioning was also assessed.

METHODS

It was an observational, cross-sectional study done at a tertiary hospital in India. Study population (n = 75) included remitted patients of bipolar disorder (n = 27), first-degree relatives of BD patients (FDR) (n = 20) and healthy controls (HC) (n = 28). Facial emotion recognition, social and occupational functioning, and quality of life (QoL) was measured using Tool for Recognition of Emotions in Neuropsychiatric Disorders, Social & Occupational Functioning Assessment Scale and World Health Organization Quality of Life-Bref, respectively, in all the participants.

RESULTS

The BD group did significantly worse in facial emotion recognition in comparison to FDR and HC groups (p < 0.001). Emotion recognition of fear, anger, surprise, and happy were most affected. FDR did not vary significantly from HC in facial emotion recognition. Lower scores on facial emotion recognition were associated with lower QoL in the social domain(p = 0.006) and poorer socio- occupational functioning scores (p = 0.01), but it was not significant within the BD group.

CONCLUSION

FERD is seen in remitted patients of bipolar disorder but not in the first -degree relatives. FERD affects social quality of life and functioning. Poorer social functioning in remitted patients of bipolar disorder might be multifactorial and cannot be attributed solely to FERD.

Emotional cognition subgroups in mood disorders: Associations with familial risk

Patients with mood disorders show heterogeneity in non-emotional cognition. However, it is unclear whether emotional cognition (EC) is characterised by similar heterogeneity. We aimed to investigate the heterogeneity in EC among remitted patients with mood disorders and explore its association with familial risk. Data from 269 partially or fully remitted patients with mood disorders, 87 of their unaffected relatives (UR) and 203 healthy controls (HC) were pooled from two cohort studies. Hierarchical cluster analysis was conducted using the EC data from patients. UR were categorised into groups consistent with their affected relatives' cluster assignment. Clusters were compared to HC on EC, non-emotional cognition, clinical characteristics and functioning.  We identified three clusters: an 'emotionally preserved' (57%), an 'emotionally blunted' (26%) and an 'emotionally volatile' cluster (17%). 'Emotionally blunted' and 'emotionally volatile' patients also presented more deficits in non-emotional cognition (global cognition read z=-0.3 and -0.5 respectively). Relatives of 'emotionally preserved' patients were more successful at dampening negative emotions (p=.01, d=0.39, 95% CI [-0.76,-0.09]), whereas UR of 'emotionally impaired' patients underperformed in verbal fluency (p=.03, d=0.46, 95% CI [.03, 0.68]) compared to HC. The existence of impaired EC groups in remitted mood disorder highlights a need to screen for and treat EC in mood disorders. Improved ability to dampen emotions in UR of 'emotionally preserved' patients may reflect a resilience marker while impaired verbal fluency in UR of 'emotionally impaired' patients may reflect distinct genetic risk profiles in these EC subgroups.

Cortical mediation of relationships between dopamine receptor D2 and cognition is absent in youth at risk of bipolar disorder

Bipolar disorder is associated with cognitive deficits and cortical changes for which the developmental dynamics are not well understood. The dopamine D2 receptor (DRD2) gene has been associated with both psychiatric disorders and cognitive variability. Here we examined the mediating role of brain structure in the relationship between DRD2 genomic variation and cognitive performance, with target cortical regions selected based on evidence of association with DRD2, bipolar disorder and/or cognition from prior literature. Participants (n = 143) were aged 12-30 years and comprised 62 first-degree relatives of bipolar patients (deemed 'at-risk'), 55 controls, and 26 patients with established bipolar disorder; all were unrelated Caucasian individuals with complete data across the three required modalities (structural magnetic resonance imaging, neuropsychological and genetic data). A DRD2 haplotype was derived from three functional polymorphisms (rs1800497, rs1076560, rs2283265) associated with alternative splicing (i.e., D2-short/-long isoforms). Moderated mediation analyses explored group differences in relationships between this DRD2 haplotype, three structural brain networks which subsume the identified cortical regions of interest (frontoparietal, dorsal-attention, and ventral-attention), and three cognitive indices (intelligence, attention, and immediate memory). Controls who were homozygous for the DRD2 major haplotype demonstrated greater cognitive performance as a result of dorsal-attention network mediation. However, this association was absent in the 'at-risk' group. This study provides the first evidence of a functional DRD2-brain-cognition pathway. The absence of typical brain-cognition relationships in young 'at-risk' individuals may reflect biological differences that precede illness onset. Further insight into early pathogenic processes may facilitate targeted early interventions.

Familial aggregation analysis of cognitive performance in early-onset bipolar disorder

We analysed the familial aggregation (familiality) of cognitive dimensions and explored their role as liability markers for early-onset bipolar disorder (EOBD). The sample comprised 99 subjects from 26 families, each with an offspring diagnosed with EOBD. Four cognitive dimensions were assessed: reasoning skills; attention and working memory; memory; and executive functions. Their familiality was investigated in the total sample and in a subset of healthy relatives. The intra-family resemblance score (IRS), a family-based index of the similarity of cognitive performance among family members, was calculated. Familiality was detected for the attention and working memory (AW) dimension in the total sample (ICC = 0.37, p = 0.0004) and in the subsample of healthy relatives (ICC = 0.37, p = 0.016). The IRS reflected that there are families with similar AW mean scores (either high or low) and families with heterogeneous scores. Families with the most common background for the AW dimension (IRS > 0) were selected and dichotomized in two groups according to the mean family AW score. This allowed differentiating families whose members had similar high scores than those with similar low scores: both patients (t = - 4.82, p = 0.0005) and relatives (t = - 5.04, p < 0.0001) of the two groups differed in their AW scores. AW dimension showed familial aggregation, suggesting its putative role as a familial vulnerability marker for EOBD. The IRS estimation allowed the identification of families with homogeneous scores for this dimension. This represents a first step towards the investigation of the underlying mechanisms of AW dimension and the identification of etiological subgroups.

Aberrant cognition in newly diagnosed patients with bipolar disorder and their unaffected relatives

BACKGROUND

Patients with bipolar disorder (BD) experience persistent impairments in both affective and non-affective cognitive function, which is associated with a worse course of illness and poor functional outcomes. Nevertheless, the temporal progression of cognitive dysfunction in BD remains unclear and the identification of objective endophenotypes can inform the aetiology of BD.

METHODS

The present study is a cross-sectional investigation of cognitive baseline data from the longitudinal Bipolar Illness Onset-study. One hundred seventy-two remitted patients newly diagnosed with BD, 52 of their unaffected relatives (UR), and 110 healthy controls (HC) were compared on a large battery of behavioural cognitive tasks tapping into non-affective (i.e. neurocognitive) and affective (i.e. emotion processing and regulation) cognition.

RESULTS

Relative to HCs, patients with BD exhibited global neurocognitive deficits (ps < 0.001), as well as aberrant emotion processing and regulation (ps ⩽ 0.011); including decreased emotional reactivity to positive social scenarios, impaired ability to down-regulate positive emotion, as well as a specific deficit in the ability to recognise surprised facial expressions. Their URs also showed a trend towards difficulties identifying surprised faces (p = 0.075). No other differences in cognitive function were found for URs compared to HCs.

CONCLUSIONS

Neurocognitive deficits and impairments within emotion processing and regulation may be illness-related deficits of BD that present after illness-onset, whereas processing of emotional faces may represent an early risk marker of BD. However, longitudinal studies are needed to examine the association between cognitive impairments and illness progression in BD.

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.

Cognitive Impairment in Patients with Bipolar Disorder: Impact of Pharmacological Treatment

Bipolar disorder is an illness characterised by periods of elated and depressed mood. These mood episodes are associated with changes in cognitive function and there is evidence to suggest that cognitive dysfunction persists during euthymia. The extent to which this is a function of the illness or a result of treatment is less clear. In this narrative review, we explore the impact of commonly used medications for bipolar disorder on cognitive function. Specific impairments in executive function and verbal memory have been noted in bipolar disorder. The impact of pharmacological treatments upon cognitive function is mixed with a number of studies reporting conflicting results. Interpretation of the data is further complicated by the variety of cognitive tests employed, study design, the relatively small numbers of patients included and confounding by indication. Overall, there is some evidence that while lithium improves some cognitive domains, it impedes others. Antipsychotics may be deleterious to cognition, although this may relate to the patient population in which they are prescribed. Sodium valproate is also associated with worse cognitive outcomes, while the impact of other antiepileptics is unclear. Overall the quality of evidence is poor and is derived from a relatively small number of studies that often do not account for the significant heterogeneity of the disorder or common comorbidities. The use of consistent methodologies and measures of cognition across studies, as well as in naturalistic settings, would enable more certain conclusions to be drawn.

Social Cognition, Language, and Social Behavior in 7-Year-Old Children at Familial High-Risk of Developing Schizophrenia or Bipolar Disorder: The Danish High Risk and Resilience Study VIA 7-A Population-Based Cohort Study

OBJECTIVE

To characterize social cognition, language, and social behavior as potentially shared vulnerability markers in children at familial high-risk of schizophrenia (FHR-SZ) and bipolar disorder (FHR-BP).

METHODS

The Danish High-Risk and Resilience Study VIA7 is a multisite population-based cohort of 522 7-year-old children extracted from the Danish registries. The population-based controls were matched to the FHR-SZ children on age, sex, and municipality. The FHR-BP group followed same inclusion criteria. Data were collected blinded to familial high-risk status. Outcomes were social cognition, language, and social behavior.

RESULTS

The analysis included 202 FHR-SZ children (girls: 46%), 120 FHR-BP children (girls: 46.7%), and 200 controls (girls: 46.5%). FHR-SZ children displayed significant deficits in language (receptive: d = -0.27, P = .006; pragmatic: d = -0.51, P < .001), social responsiveness (d = -0.54, P < .001), and adaptive social functioning (d = -0.47, P < .001) compared to controls after Bonferroni correction. Compared to FHR-BP children, FHR-SZ children performed significantly poorer on adaptive social functioning (d = -0.29, P = .007) after Bonferroni correction. FHR-BP and FHR-SZ children showed no significant social cognitive impairments compared to controls after Bonferroni correction.

CONCLUSION

Language, social responsiveness, and adaptive social functioning deficits seem associated with FHR-SZ but not FHR-BP in this developmental phase. The pattern of results suggests adaptive social functioning impairments may not be shared between FHR-BP and FHR-SZ in this developmental phase and thus not reflective of the shared risk factors for schizophrenia and bipolar disorder.

Is aberrant affective cognition an endophenotype for affective disorders? - A monozygotic twin study

BACKGROUND

Identification of endophenotypes can improve prevention, detection and development of new treatments. We therefore investigated whether aberrant affective cognition constitutes an endophenotype for affective disorders by being present in monozygotic (MZ) twins with unipolar or bipolar disorder in partial remission (i.e. affected) and their unaffected co-twins (i.e. high-risk) relative to twins with no family history of affective disorder (i.e. low-risk).

METHODS

We conducted an assessor blind cross-sectional study from 2014 to 2017 of MZ twins using Danish population-based registers in recruitment. Twins attended one test session involving neurocognitive testing, clinical ratings and questionnaires. Main outcomes were attention to and recognition of emotional facial expressions, the memory of emotional self-referential words, emotion regulation and coping strategies.

RESULTS

Participants were 103 affected, 44 high-risk and 36 low-risk MZ twins. Groups were demographically well-balanced and showed comparable non-affective cognitive performance. We observed no aberrant affective cognition in affected and high-risk relative to low-risk twins. However, high-risk twins displayed attentional avoidance of emotional faces (ps ⩽ 0.009) and more use of task-oriented coping strategies (p = 0.01) compared with affected twins. In contrast did affected twins show more emotion-oriented coping than high- and low-risk twins (ps ⩽ 0.004).

CONCLUSIONS

Our findings provide no support of aberrant affective cognition as an endophenotype for affective disorders. High-risk twins' attentional avoidance of emotional faces and greater use of task-oriented coping strategies may reflect compensatory mechanisms.

Neuropsychological Functioning and Temperament Traits in a Czech Sample of Children and Adolescents at Familial Risk of Bipolar Disorder

Background: Although a positive family history is the strongest predictor for bipolar disorder (BD), most offspring of BD parents (BO) will not develop the disorder. Identification of vulnerability markers for BD is essential for specific individual risk estimation. Impairments in cognitive functioning and the presence of specific temperament traits are considered promising candidates. Methods: Sixty-three BO (48% female; 11.8 ± 3.3 years) and 54 control offspring (CO; 44% female; 12.3 ± 3.2 years) comparable in sex (p = 0.4) and age (p = 0.4) were enrolled. Detection of current sub/threshold mood symptoms by the Kiddie Schedule for Affective Disorders and Schizophrenia and General Behavior Inventory was applied to separate BO into ultrahigh-risk (UHR) and high-risk (HR) subgroups. Cognitive functions were tested by the Developmental Neuropsychological Assessment II test battery, d2 Test of Attention, and Amsterdam Neuropsychological Tasks. Temperament was assessed by the Temperament in Middle Childhood and Early Adolescent Temperament Questionnaires. Results: The BO sample consisted of 5 BD, 17 UHR, and 41 HR participants. We did not observe any significant differences between the BO and CO groups or between the UHR, HR, and CO subgroups (Hedges' g = 0.21-0.39) in cognitive functioning. The BO differed significantly in some temperament traits from the CO (g = 0.42-0.61), while the UHR subgroup exhibited lower effortful control and attention focusing than both HR and CO participants (g = 0.92-1.19). Limitations: The cross-sectional design and wide age range of the sample limited our findings. Conclusions: Neuropsychological impairment does not seem to be a trait marker of BD in the premorbid stage. Temperament with low effortful control and low attention focusing might be associated with the development of mood disorders in BO.

Neurocognitive deficits in a transdiagnostic clinical staging model

There is a growing literature which suggests that neurocognitive deficits may be markers of susceptibility for serious mental illness development. This study assessed neurocognitive functioning in a sample of youth at risk of serious mental illness across different clinical stages as described by McGorry and colleagues and compared them to healthy controls. The sample was 243 male and female youths aged 12-26 and included: asymptomatic participants with psychiatric risk factors (Stage 0; n = 41); youth with early mood or anxiety symptoms (Stage 1a; n = 52); youth with attenuated psychiatric syndromes (Stages 1b; n = 108); and healthy controls (n = 42). The neurocognitive battery included IQ measures and the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery. Participants in Stage 1b had lower scores than healthy controls on the composite score of neurocognitive performance, across all IQ measures, and in the domains of processing speed, working memory, attention and problem solving. They also had lower scores than subjects in Stage 0 across most IQ measures and in the domains of processing speed and working memory. This study increases what is known about neurocognitive performance associated with different stages of serious mental illness development.

Vulnerabilities in sequencing and task switching in healthy youth offspring of parents with mood disorders

INTRODUCTION

Visuospatial processing and task switching are impaired in individuals with mood disorders. It is unknown whether early deficits are present before mood symptom on set or are related to risk for a specific type of mood disorder. To investigate, we compared visual attention and task switching during sequencing among never-disordered youth with parental family histories of bipolar (BD) and major depressive disorders (MDD) and healthy controls (HC) with no personal or family history of psychopathology.

METHOD

8-17-year-old youth of parents with BD (n = 31, "BD-risk"), youth of parents with MDD (n = 49, "MDD-risk"), and demographically similar HC (n = 31, "HC") were examined using the Delis-Kaplan Executive Functioning System Trail Making Test. Seed-based resting-state functional connectivity (RSFC) was collected from a subset of 88 participants (25 BD-risk, 37 MDD-risk, 26 HC) to investigate group differences in RSFC related to visuospatial processing.

RESULTS

BD-risk and MDD-risk offspring had impaired sequencing and task switching, demonstrated by reduced scores on visual scanning, F(2, 108) = 4.12, p = .02, number sequencing, F(2, 88) = 4.75, p = .01, letter sequencing, F(2, 108) = 4.24, p = .02, and number-letter sequencing, F(2, 108) = 4.66, p = .01, compared to scores in HC. RSFC between the posterior cingulate (PCC) and clusters in the subcallosal cortex, amygdala, and hippocampus significantly differed among HC, BD-risk, and MDD-risk groups. PCC-subcallosal/limbic RSFC was positively coupled in the MDD-risk and BD-risk groups and negatively coupled in HCs.

CONCLUSIONS

Youth at familial risk for mood disorders demonstrate visuospatial deficits early in the processing stream. Improved methods for identifying at-risk children with the earliest possible neurocognitive impairments may inform remediation strategies that could prevent mood disorders.

Clinical predictors of conversion to bipolar disorder in a prospective longitudinal familial high-risk sample: focus on depressive features

BACKGROUND

Identifying clinical features that predict conversion to bipolar disorder (BD) in those at high familial risk (HR) would assist in identifying a more focused population for early intervention.

METHOD

In total 287 participants aged 12-30 (163 HR with a first-degree relative with BD and 124 controls (CONs)) were followed annually for a median of 5 years. We used the baseline presence of DSM-IV depressive, anxiety, behavioural and substance use disorders, as well as a constellation of specific depressive symptoms (as identified by the Probabilistic Approach to Bipolar Depression) to predict the subsequent development of hypo/manic episodes.

RESULTS

At baseline, HR participants were significantly more likely to report ⩾4 Probabilistic features (40.4%) when depressed than CONs (6.7%; p < .05). Nineteen HR subjects later developed either threshold (n = 8; 4.9%) or subthreshold (n = 11; 6.7%) hypo/mania. The presence of ⩾4 Probabilistic features was associated with a seven-fold increase in the risk of 'conversion' to threshold BD (hazard ratio = 6.9, p < .05) above and beyond the fourteen-fold increase in risk related to major depressive episodes (MDEs) per se (hazard ratio = 13.9, p < .05). Individual depressive features predicting conversion were psychomotor retardation and ⩾5 MDEs. Behavioural disorders only predicted conversion to subthreshold BD (hazard ratio = 5.23, p < .01), while anxiety and substance disorders did not predict either threshold or subthreshold hypo/mania.

CONCLUSIONS

This study suggests that specific depressive characteristics substantially increase the risk of young people at familial risk of BD going on to develop future hypo/manic episodes and may identify a more targeted HR population for the development of early intervention programs.

Increased sensitivity to positive social stimuli in monozygotic twins at risk of bipolar vs. unipolar disorder

BACKGROUND

Abnormalities in affective cognition are putative endophenotypes for bipolar and unipolar disorders but it is unclear whether some abnormalities are disorder-specific. We therefore investigated affective cognition in monozygotic twins at familial risk of bipolar disorder relative to those at risk of unipolar disorder and to low-risk twins.

METHODS

Seventy monozygotic twins with a co-twin history of bipolar disorder (n = 11), of unipolar disorder (n = 38) or without co-twin history of affective disorder (n = 21) were included. Variables of interest were recognition of and vigilance to emotional faces, emotional reactivity and -regulation in social scenarios and non-affective cognition.

RESULTS

Twins at familial risk of bipolar disorder showed increased recognition of low to moderate intensity of happy facial expressions relative to both unipolar disorder high-risk twins and low-risk twins. Bipolar disorder high-risk twins also displayed supraliminal attentional avoidance of happy faces compared with unipolar disorder high-risk twins and greater emotional reactivity in positive and neutral social scenarios and less reactivity in negative social scenarios than low-risk twins. In contrast with our hypothesis, there was no negative bias in unipolar disorder high-risk twins. There were no differences between the groups in demographic characteristics or non-affective cognition.

LIMITATIONS

The modest sample size limited the statistical power of the study.

CONCLUSIONS

Increased sensitivity and reactivity to positive social stimuli may be a neurocognitive endophenotype that is specific for bipolar disorder. If replicated in larger samples, this 'positive endophenotype' could potentially aid future diagnostic differentiation between unipolar and bipolar disorder.

Intellectual Functioning in Offspring of Parents with Bipolar Disorder: A Review of the Literature

Impaired intellectual functioning is an important risk factor for the emergence of severe mental illness. Unlike many other forms of mental disorder however, the association between bipolar disorder and intellectual deficits is unclear. In this narrative review, we examine the current evidence on intellectual functioning in children and adolescents at risk for developing bipolar disorder. The results are based on 18 independent, peer-reviewed publications from 1980 to 2017 that met criteria for this study. The findings yielded no consistent evidence of lower or higher intellectual quotient (IQ) in offspring of parents diagnosed with bipolar disorder. Some tentative evidence was found for lower performance IQ in offspring of bipolar parents as compared to controls. It is recommended that future research examine variability in intellectual functioning and potential moderators. These findings demonstrate the need to examine how intellectual functioning unfolds across development given the potential role of IQ as a marker of vulnerability or resilience in youth at high risk for affective disorders.

Disentangling Working Memory Functioning in Mood States of Bipolar Disorder: A Systematic Review

Working memory (WM) deficits are often reported in patients with Bipolar Disorder (BD). However, it is not clear about the nature of these WM deficits (update or serial order processes) and their association with each BD states (euthymic, mania, and depressive). This review investigated the association between BD patient's states and the functioning of WM components. For this purpose, we carried out a systematic review fulfilling a search in the databases Medline, Scopus, SciELO, and Web of Science using specific terms in the abstracts of the articles that generated 212 outcomes in the restricted period from 2005 to 2016. Twenty-three papers were selected, completely read, and analyzed using PICOS strategy. The mood episodes predicted deficits in different components of WM in BD patients (the phonological loop or visuospatial sketchpad) and were associated with different WM processes (updating and serial recall). Lower cognitive scores persist even in remission of symptoms. This result suggests that WM deficit apparently is stage-independent in BD patients. Furthermore, findings suggest that the neutral point on Hedonic Detector component of WM could be maladjusted by BD.

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.

Summaries of plenary and selected symposia sessions at the XXIV World Congress of Psychiatric Genetics; Jerusalem, Israel; 30 October 2016-3 November 2016

The XXII World Congress of Psychiatric Genetics, sponsored by the International Society of Psychiatric Genetics, took place in Jerusalem, Israel, from 30 October 2016 to 3 November 2016. A total of 372 participants gathered to discuss the latest findings in the field. The following report was written by early career investigator travel awardees, and student and postdoctoral attendees. Each was assigned one or more sessions as a rapporteur. This manuscript represents topics covered in most, but not all of the presentations during the conference, and contains some of the major notable new findings reported.

Neurobiology of Risk for Bipolar Disorder

Bipolar disorder (BD) is a chronic mental illness which follows a relapsing and remitting course and requires lifetime treatment. The lack of biological markers for BD is a major difficulty in clinical practice. Exploring multiple endophenotypes to fit in multivariate genetic models for BD is an important element in the process of finding tools to facilitate early diagnosis, early intervention, prevention of new episodes, and follow-up of treatment response in BD. Reviewing of studies on neuroimaging, neurocognition, and biochemical parameters in populations with high genetic risk for the illness can yield an integrative perspective on the neurobiology of risk for BD. The most up-to-date data reveals consistent deficits in executive function, response inhibition, verbal memory/learning, verbal fluency, and processing speed in risk groups for BD. Functional magnetic resonance imaging (fMRI) studies report alterations in the activity of the inferior frontal gyrus, medial prefrontal cortex, and limbic areas, particularly in the amygdala in unaffected first-degree relatives (FDR) of BD compared to healthy controls. Risk groups for BD also present altered immune and neurochemical modulation. Despite inconsistencies, accumulating data reveals cognitive and imaging markers for risk and to a less extent resilience of BD. Findings on neural modulation markers are preliminary and require further studies. Although the knowledge on the neurobiology of risk for BD has been inadequate to provide benefits for clinical practice, further studies on structural and functional changes in the brain, neurocognitive functioning, and neurochemical modulation have a potential to reveal biomarkers for risk and resilience for BD. Multimodal, multicenter, population-based studies with large sample size allowing for homogeneous subgroup analyses will immensely contribute to the elucidation of biological markers for risk for BD in an integrative model.

Differences in cognitive impairment between schizophrenia and bipolar disorder: Considering the role of heterogeneity

Schizophrenia is associated with significant cognitive impairment. Bipolar disorder (BD) also presents with cognitive deficits that are similar to, albeit less severe, than those reported in schizophrenia. There has been controversy over whether selective deficits in social cognition or developmental trajectory of cognitive deficits can distinguish schizophrenia from BD. Also, available studies have not generally considered the potential effect of cognitive heterogeneity within the two disorders on between-group differences. The current review examines the evidence on the specificity of social cognitive deficits and early neurocognitive impairment to schizophrenia and explores the overall outcome of studies investigating within and cross-diagnosis cognitive heterogeneity in schizophrenia and BD. Current evidence does not support the specificity of social cognitive impairment to schizophrenia. Available studies also suggest that cognitive impairment in premorbid and early stages is evident not only in schizophrenia but also in many BD patients. Both schizophrenia and BD have a number of cognitive subgroups, including severe impairment, good functioning, and one or more selective or modest impairment clusters. While both disorders are represented in each cognitive subgroup, there are significant cross-diagnostic differences regarding prevalences of individuals belonging to the severe impairment and good functioning subgroups. Individuals with schizophrenia are much more likely to exhibit severe cognitive impairment than individuals with BD and good cognitive functioning is more often observed in BD patients than schizophrenia patients. Further identification of the neurobiological and genetic characteristics of the cognitive subgroups in major psychoses can improve the validity of diagnostic systems and can advance the development of personalized management approaches, including cognitive remediation.

Interhemispheric white matter integrity in young people with bipolar disorder and at high genetic risk

BACKGROUND

White matter (WM) impairments have been reported in patients with bipolar disorder (BD) and those at high familial risk of developing BD. However, the distribution of these impairments has not been well characterized. Few studies have examined WM integrity in young people early in the course of illness and in individuals at familial risk who have not yet passed the peak age of onset.

METHOD

WM integrity was examined in 63 BD subjects, 150 high-risk (HR) individuals and 111 participants with no family history of mental illness (CON). All subjects were aged 12 to 30 years.

RESULTS

This young BD group had significantly lower fractional anisotropy within the genu of the corpus callosum (CC) compared with the CON and HR groups. Moreover, the abnormality in the genu of the CC was also present in HR participants with recurrent major depressive disorder (MDD) (n = 16) compared with CON participants.

CONCLUSIONS

Our findings provide important validation of interhemispheric abnormalities in BD patients. The novel finding in HR subjects with recurrent MDD - a group at particular risk of future hypo/manic episodes - suggests that this may potentially represent a trait marker for BD, though this will need to be confirmed in longitudinal follow-up studies.