Cognitive dysfunction in bipolar disorder and schizophrenia: a systematic review of meta-analyses

Impairment in emotion perception from body movements in individuals with bipolar I and bipolar II disorder is associated with functional capacity

Background

Individuals with bipolar disorder present with moderate impairments in social cognition during the euthymic state. The impairment extends to theory of mind and to the perception of emotion in faces and voices, but it is unclear if emotion perception from body movements is affected. The main aim of this study was to examine if participants with bipolar disorder perform worse than healthy control participants on a task using point-light displays of human full figures moving in a manner indicative of a basic emotion (angry, happy, sad, fearful, neutral/no emotion). A secondary research question was whether diagnostic subtypes (bipolar I, bipolar II) and history of psychosis impacted on this type of emotion perception. Finally, symptomatic, neurocognitive, and functional correlates of emotion perception from body movements were investigated.

Methods

Fifty-three individuals with bipolar I (n = 29) or bipolar II (n = 24) disorder, and 84 healthy control participants were assessed for emotion perception from body movements. The bipolar group also underwent clinical, cognitive, and functional assessment. Research questions were analyzed using analyses of variance and bivariate correlations.

Results

The bipolar disorder group differed significantly from healthy control participants for emotion perception from body movements (Cohen’s d = 0.40). Analyses of variance yielded no effects of sex, diagnostic subtype (bipolar I, bipolar II), or history of psychosis. There was an effect of emotion, indicating that some emotions are easier to recognize. The lack of a significant group × emotion interaction effect points, however, to this being so regardless of the presence of bipolar disorder. Performance was unrelated to manic and depressive symptom load but showed significant associations with neurocognition and functional capacity.

Conclusions

Individuals with bipolar disorder had a small but significant impairment in the ability to perceive emotions from body movement. The impairment was global, i.e., affecting all emotions and equally present for males and females. The impairment was associated with neurocognition and functional capacity, but not symptom load. Our findings identify pathopsychological factors underlying the functional impairment in bipolar disorder and suggest the consideration of social cognition training as part of the treatment for bipolar disorder.

Cognitive Impairment in Bipolar Disorder: Treatment and Prevention Strategies

Over the last decade, there has been a growing appreciation of the importance of identifying and treating cognitive impairment associated with bipolar disorder, since it persists in remission periods. Evidence indicates that neurocognitive dysfunction may significantly influence patients' psychosocial outcomes. An ever-increasing body of research seeks to achieve a better understanding of potential moderators contributing to cognitive impairment in bipolar disorder in order to develop prevention strategies and effective treatments. This review provides an overview of the available data from studies examining treatments for cognitive dysfunction in bipolar disorder as well as potential novel treatments, from both pharmacological and psychological perspectives. All these data encourage the development of further studies to find effective strategies to prevent and treat cognitive impairment associated with bipolar disorder. These efforts may ultimately lead to an improvement of psychosocial functioning in these patients.

Relationship Between Objectively Measured Sedentary Behavior and Cognitive Performance in Patients With Schizophrenia Vs Controls

OBJECTIVE

Sedentary behavior (SB) is associated with poor cognitive performance in the general population. Although people with schizophrenia are highly sedentary and experience marked cognitive impairments, no study has investigated the relationship between SB and cognition in people with schizophrenia.

METHODS

A total of 199 inpatients with schizophrenia (mean [SD] age 44.0 [9.9] years, 61.3% male, mean [SD] illness duration 23.8 [6.5]) and 60 age and sex matched controls were recruited. Sedentary behavior and physical activity (PA) were captured for 7 consecutive days with an accelerometer. Cognitive performance was assessed using the Vienna Test System, and the Grooved Pegboard Test. Multivariate regression analyses adjusting for important confounders including positive and negative symptoms, illness duration, medication, and PA were conducted.

RESULTS

The 199 patients with schizophrenia engaged in significantly more SB vs controls (581.1 (SD 127.6) vs 336.4 (SD 107.9) min per day, P < .001) and performed worse in all cognitive performance measures (all P < .001). Compared to patients with high levels of SB (n = 89), patients with lower levels of SB (n = 110) had significantly (P < .05) better motor reaction time and cognitive processing. In the fully adjusted multivariate analysis, SB was independently associated with slower motor reaction time (β = .162, P < .05) but not other cognitive outcomes. Lower levels of PA were independently associated with worse attention and processing speed (P < .05).

CONCLUSION

Our data suggest that higher levels of sedentary behavior and physical inactivity are independently associated with worse performance across several cognitive domains. Interventions targeting reductions in SB and increased PA should be explored.

Cognitive-behavioral rehabilitation vs. treatment as usual for bipolar patients: study protocol for a randomized controlled trial

BACKGROUND

Bipolar disorder (BD) is commonly associated with cognitive and functional impairments even during remission periods, and although a growing number of studies have demonstrated the benefits of psychotherapy as an add-on to pharmacological treatment, its effectiveness appears to be less compelling in severe presentations of the disorder. New interventions have attempted to improve cognitive functioning in BD patients, but results have been mixed.

METHODS

The study consists of a clinical trial comparing a new structured group intervention, called "Cognitive-Behavioral Rehabilitation," with treatment as usual (TAU) for bipolar patients. The new approach is a combination of cognitive behavioral strategies and cognitive remediation exercises, consisting of 12 weekly group sessions of 90 min each. To be included in the study, patients must be diagnosed with BD type I or II, aged 18-55 years, in full or partial remission, and have an IQ of at least 80. A comprehensive neuropsychological battery, followed by mood, social functioning, and quality of life assessments will occur in three moments: pre and post intervention and 12 months later. The primary outcome of the study is to compare the time, in weeks, that the first full mood episode appears in patients who participated in either group of the study. Secondary outcome will include improvement in cognitive functions.

DISCUSSION

This is the first controlled trial assessing the validity and effectiveness of the new "Cognitive-Behavioral Rehabilitation" intervention in preventing new mood episodes and improving cognitive and functional impairments.

TRIAL REGISTRATION

Clinicaltrial.gov, NCT02766361 . Registered on 2 May 2016.

Dcc haploinsufficiency regulates dopamine receptor expression across postnatal lifespan

Adolescence is a period during which the medial prefrontal cortex (mPFC) undergoes significant remodeling. The netrin-1 receptor, deleted in colorectal cancer (DCC), controls the extent and organization of mPFC dopamine connectivity during adolescence and in turn directs mPFC functional and structural maturation. Dcc haploinsufficiency leads to increased mPFC dopamine input, which causes improved cognitive processing and resilience to behavioral effects of stimulant drugs of abuse. Here we examine the effects of Dcc haploinsufficiency on the dynamic expression of dopamine receptors in forebrain targets of C57BL6 mice. We conducted quantitative receptor autoradiography experiments with [³H]SCH-23390 or [³H]raclopride to characterize D1 and D2 receptor expression in mPFC and striatal regions in male Dcc haploinsufficient and wild-type mice. We generated autoradiograms at early adolescence (PND21±1), mid-adolescence (PND35±2), and adulthood (PND75±15). C57BL6 mice exhibit overexpression and pruning of D1, but not D2, receptors in striatal regions, and a lack of dopamine receptor pruning in the mPFC. We observed age- and region-specific differences in D1 and D2 receptor density between Dcc haploinsufficient and wild-type mice. Notably, neither group shows the typical pattern of mPFC dopamine receptor pruning in adolescence, but adult haploinsufficient mice show increased D2 receptor density in the mPFC. These results show that DCC receptors contribute to the dynamic refinement of D1 and D2 receptor expression in striatal regions across adolescence. The age-dependent expression of dopamine receptor in C57BL6 mice shows marked differences from previous characterizations in rats.

Use of the MATRICS consensus cognitive battery (MCCB) to evaluate cognitive deficits in bipolar disorder: A systematic review and meta-analysis

BACKGROUND

The Measurement and Treatment Research to Improve Cognition Schizophrenia Consensus Cognitive Battery (MCCB) has also been proposed for use in clinical trials to assess cognitive deficits in patients with bipolar disorder (BD). The aim of this study was to evaluate cognitive function assessed by the MCCB in BD.

METHODS

A literature search of the PubMed, Embase, PsycINFO, SCI, Cochrane Library databases and the Cochrane Controlled Trials Register was conducted. Case reports, reviews and meta-analyses were excluded and a systematic review of the remaining studies of cognitive function in BD was carried out. The cognitive outcome measure was the MCCB, including 7 domains and overall cognition. A random-effects model was applied.

RESULTS

Eighty eight studies were initially identified. Seven clinical studies comprising a total of 487 patients and 570 healthy controls (HC) were included in the meta-analysis. Patients with BD performed worse than HC in overall cognition and processing speed with a large effect size of >0.8; with a medium effect size (0.5-0.8) in attention, working memory, verbal learning and visual learning; and with a small effect size (0.2-0.5) in reasoning and problem solving and social cognition.

CONCLUSION

Patients with BD performed worse than HC in overall cognition and all cognitive domains of the MCCB. Cognitive deficits in domains of processing speed and working memory are prominent in patients with BD. Our findings suggest that MCCB can be usefully applied in BD.

Validation of the Chinese version of Brief Assessment of Cognition in Schizophrenia

OBJECTIVE

A test battery that measures cognitive function impairment in patients with schizophrenia, the Brief Assessment of Cognition in Schizophrenia (BACS), has been translated into various languages and validated. This study aimed to test the reliability and validity of the Chinese version of the BACS in a Chinese-speaking population.

METHODS

All participants in this study (66 patients with schizophrenia [mean age: 41.2 years, 57.6% male] and 66 age- and sex-matched healthy controls) were from Taiwan and assessed using the BACS and the University of California, San Diego (UCSD) Performance-Based Skills Assessment, Brief Version (UPSA-B). Thirty-eight of the 66 patients with schizophrenia received a reassessment using the BACS.

RESULTS

The BACS had good test-retest reliability, and all BACS subtests had statistically insignificant practice effects. Principal components analysis demonstrated that a one-factor solution best fits our dataset (60.9% of the variance). In both patients and controls, the BACS composite scores were positively correlated with all BACS subscales (P<0.001) and UPSA-B scales (P<0.001). Furthermore, all BACS subtests (verbal memory, working memory, motor speed, verbal fluency, attention and processing speed, and executive function) significantly differentiated patients with schizophrenia from healthy controls (P<0.001), and the BACS composite score had the best discriminative validity (P<0.001).

CONCLUSION

The Chinese version of the BACS exhibits satisfactory psychometric properties, including high test-retest reliability, high internal consistency, acceptable concurrent validity, and good discriminant validity. We suggest that the BACS is a reliable and practical tool for assessing cognitive function in patients with schizophrenia.