"Influence of modifiable and non-modifiable variables on functioning in bipolar disorder: a path analytical study".

OBJECTIVE: The aim of this study was to investigate the influence of modifiable (mood, cognitive reserve, cognitive performance) and non-modifiable factors (diagnosis, suicide attempts, substance use, age) on self-reported functioning in BD. METHODS: 103 adults with no mood disorders and 95 individuals with BD completed the WHODAS 2.0, in addition to a neuropsychological battery and diagnostic assessments. Path analysis was then used to analyse the relationships between modifiable and non-modifiable predictors of functioning in the sample. RESULTS: Cognitive reserve and age had an indirect influence on individual functioning, mediated by cognitive performance. The influence of diagnosis and depressive symptoms on functioning was partly direct, and partly mediated by cognition. The presence of psychiatric comorbidities in addition to BD also had a significant influence on individual functioning. CONCLUSIONS: Initiatives focussed on modifiable factors such as depressive symptoms and cognitively stimulating activities, which increase cognitive reserve, may be a useful complement to existing treatments and help patients achieve functional recovery. KEY POINTS Individual functioning was influenced by cognitive performance, cognitive reserve, age, diagnosis and depressive symptoms. Executive functioning mediated the influence of age and cognitive reserve on individual functioning. Interventions focussed on depressive symptoms and cognitive stimulation may help patients achieve functional recovery.

The effects of cognitive reserve and depressive symptoms on cognitive performance in major depression and bipolar disorder.

BACKGROUND: Significant heterogeneity is observed in the cognitive profiles of bipolar disorder (BD) and major depression (MDD), characterized in part by differences in individual and clinical variables such as cognitive reserve (CR) and depression severity. However, no other study evaluated how this variables may interact regarding neurocognitive functioning. The aim of the present exploratory study was to evaluate the interaction between different depressive symptoms severity, CR and diagnosis with neurocognitive functioning. METHOD: 202 participants (MDD=91; BD=111) classified either as euthymic, with mild depression or moderate to severe depression, and low or high CR completed a neuropsychological evaluation of verbal fluency, working memory (WM), inhibitory control (IC), cognitive flexibility (CF) and attention (Att). RESULTS: Neuroprotective effects of CR were observed in patients with BD within a major depressive episode in WM, IC, FC and Att. In MDD, CR acted as a neuroprotective factor during euthymia and moderate to severe depression in the same cognitive functions. CR and depression severity differentiated the cognitive profiles of individuals with BD and MDD. LIMITATIONS: Some variables related to neurocognitive performance like medication use, number of mood episodes, illness duration or previous hospitalizations were not controlled. CONCLUSION: CR may be protective against cognitive impairment in both BD and MDD, and these effects were observed in euthymia and during depressive episodes of varying severity. These findings highlight the importance of investigating such variables in the neuropsychological evaluation of mood disorders, which may help to understand the cognitive heterogeneity within these populations.

Neuropsychological Clustering in Bipolar and Major Depressive Disorder.

OBJECTIVES: Cognitive dysfunction is a key feature of major depressive (MDD) and bipolar (BD) disorders. However, rather than a single cognitive profile corresponding to each diagnostic categories, recent studies have identified significant intra- and cross-diagnostic variability in patterns of cognitive impairment. The goal of this study was to contribute to the literature on cognitive heterogeneity in mood disorders by identifying cognitive subprofiles in a population of patients with MDD, BD type I, BD type II, and healthy adults. METHODS: Participants completed a neuropsychological battery; scores were converted into Z-scores using normative data and submitted to hierarchical cluster analysis. RESULTS: Three distinct neuropsychological clusters were identified: (1) a large cluster containing mostly control participants, as well as some patients with BD and MDD, who performed at above-average levels on all neuropsychological domains; (2) a cluster containing some patients from all diagnostic groups, as well as healthy controls, who performed worse than cluster 1 on most tasks, and showed impairments in motor inhibition and verbal fluency; (3) a cluster containing mostly patients with mood disorders with severe impairments in verbal inhibition and cognitive flexibility. CONCLUSIONS: These findings revealed multiple cognitive profiles within diagnostic categories, as well as significant cross-diagnostic overlap, highlighting the importance of developing more specific treatment approaches which consider patients' demographic and cognitive profiles in addition to their diagnosis. (JINS, 2017, 23, 584-593).

The predictive role of daily cognitive stimulation on executive functions in bipolar disorder.

This study aimed to estimate the predictive role of clinical and demographic variables on the three core executive functions (EF) - working memory (WM), inhibitory control (IC) and cognitive flexibility (CF) - in bipolar disorder (BD). The sample consisted of 38 patients with BD type I, 39 with BD type II, and 106 control participants with no mood disorders. Subjects completed the Hayling Test, Trail Making Test, Digit Span Backwards, Sentence Word Span Test, and Stroop Color-Word Test. Composite scores for WM, IC and CF were calculated, and their correlations with clinical and demographic variables were analyzed. Stepwise hierarchical regression models including all significant correlates, gender, and diagnosis, revealed that the frequency of reading and writing habits (FRWH), IQ and diagnosis predicted 38.1% of the variance in IC. Diagnosis and IQ predicted 24.9% of the variance in WM scores. CF was predicted by the FRWH only, which accounted for 7.6% of the variance in this construct. These results suggest that daily cognitive stimulation through reading and writing make a significant positive contribution to executive functioning in BD, even in the absence of continued education. These and other forms of routine cognitive stimulation should be further emphasized in intervention programs for BD.