Neuropsychology of Bipolar Disorder

Processing speed and sustained attention in bipolar disorder and major depressive disorder: A systematic review and meta-analysis

OBJECTIVES

Cognitive impairment is a core feature of bipolar disorder (BD) and major depressive disorder (MDD). Deficits in processing speed (PS) and sustained attention (SA) may be particularly impaired and may underpin a broader profile of deficits, however current knowledge of the nature of these impairments is limited by heterogeneous results in the literature. Few reviews to date have attempted to disentangle sources of heterogeneity to assess the presence and magnitude of impairments in PS and SA in BD and MDD.

METHODS

One hundred and three studies were reviewed to examine performance in tests of PS and SA in BD (n = 3452) and MDD (n = 5461) compared to healthy controls (n = 8016). Neuropsychological methodology used in the literature was summarised. Data were meta-analysed to assess impairments in PS and SA for each neuropsychological test separately. Subgroup analysis was performed across mood states to investigate sources of heterogeneity.

RESULTS

Impairments were found across most neuropsychological tests, with small to large effect sizes for BD (range: d = 0.19-0.96) and MDD (range: d = 0.29-0.86). Impairments were present in symptomatic states and euthymia in most cases. Some outcome measures were not impaired in euthymia. Heterogeneity was observed for most neuropsychological tests and remained after separating by mood state. There inadequate data to meta-analyse some outcome measures, particularly for symptomatic groups.

CONCLUSION

Impairments in PS and SA in BD and MDD can be observed across most neuropsychological tests. Future research should further investigate the nature of these impairments across mood states, controlling for clinical confounds.

Effect of mindfulness-based cognitive therapy vs. psychoeducational intervention on plasma brain-derived neurotrophic factor and cognitive function in bipolar patients: a randomized controlled trial

Introduction

Few controlled trials have assessed the benefits of Mindfulness Based Cognitive Therapy (MBCT) on cognitive functions and brain-derived neurotrophic factor (BDNF) in bipolar disorder (BD). This study aims to evaluate the impact of MBCT adjunctive treatment on these variables. Main hypothesis was that MBCT would improve cognitive functioning and BDNF more than Psychoeducation and TAU.

Methods

Randomized, multicenter, prospective and single-blinded trial. Included BD outpatients randomly assigned to three treatment arms: MBCT plus treatment as usual (TAU), Psychoeducation plus Tau and TAU. Cognitive functions were assessed with Continuous Performance Test-III, Stroop Test, Trail Making Test, Digit Span and Letter-Number Sequencing from Wechsler Adult Intelligence Scale III, Face Emotion Identification Task and Face Emotion Discrimination Task. BDNF serum level was measured with ELISA. Patients were assessed at baseline, 8 weeks and 6 months.

Results

Eighty-four patients were recruited (TAU = 10, Psychoeducation = 34, MBCT = 40). No significant differences between treatment groups were found. MBCT does not achieve better results than Psychoeducation or TAU.

Discussion

Being Psychoeducation and TAU efficient interventions, as well as the scarce duration of a more complex intervention, such as MBCT, are suggested as explanatory variables of these results.

Trial registration

ClinicalTrials.gov: NCT02133170. Registered 04/30/2014.

Social cognition and psychosocial functioning in schizophrenia and bipolar disorder: Theory of mind as a key to understand schizophrenia dysfunction

Functional impairment is a common symptom in schizophrenia (SZ) and bipolar disorder (BD). Pharmacological treatments have limited functional recovery in both disorders. Social cognition, a cognitive process, has been associated with functioning in mental disorders. Theory of mind (ToM) is considered a key factor in understanding the social cognitive deficits in SZ and BD. Our study aimed to investigate the relationship between ToM and functioning in SZ, BD, and healthy controls (HC) and compare ToM and functioning impairments between groups. A total of 208 participants (HC n = 69; BD n = 89; SZ n = 50) were evaluated with the Functioning Assessment Short Test (FAST), Reading the Mind in the Eyes Test (RMET), the Vocabulary subtest of the Wechsler Abbreviated Scale for Intelligence (WASI) and the Hopkins Verbal Learning Test - Revised (HVLT-R). Comparisons of RMET between low- and high-functioning individuals and multiple linear regression analyses were conducted for each group. Multiple regression analysis revealed that the association between ToM and psychosocial functioning was observed only in SZ (β = -1.352, p = 0.008). Low-functioning SZ participants showed a lower ToM performance compared to participants with high-functioning SZ (t = 1.80, p = 0.039, Cohen's d = 0.938). No significant associations were found in the other groups. ToM is essential to understand the functional impairment in SZ, more than in BD. Furthermore, ToM may be a primary target for intervention strategies in improving functioning in SZ.

Variation in self and familiar facial recognition in bipolar disorder patients at different clinical stages

Previous studies suggest a close relationship between self-disorders and schizophrenia or unipolar depression. However, few studies have explored the characteristics of self-processing in bipolar disorder (BD) during different clinical states. This study compared the differences in self-face recognition (SFR) among patients with bipolar mania (BPM), bipolar depression (BPD), bipolar remission (RM), and healthy controls (HC). Images of subject's own face, a familiar face, and an unfamiliar face were combined in pairs at a certain proportion to obtain three types of blended images. We then compared the tendency between BD and HC while judging two kinds of blended faces emerging from presentation software. The results showed that the BPM and BPD groups seemed to lack an advantage in self-recognition. Self-processing and familiarity processing were significantly enhanced in BPM patients, while only familiarity processing was enhanced in BPD. The severity of clinical symptoms was not significantly correlated with self-bias or familiarity bias in BD.