Neurocognitive impairment in bipolar disorder patients: functional implications

BACKGROUND: Functional recovery among treated bipolar disorder (BPD) patients is far less likely than syndromal and even symptomatic recovery. We hypothesized that increasingly well-documented aspects of cognitive impairment may contribute to poor functional outcomes in BPD patients, and reviewed the available research on the topic. METHODS: Computerized literature searching identified 12 studies with 13 comparisons that simultaneously evaluated cognitive and functional status in euthymic (n = 8) or non-euthymic (n = 5 comparisons) adult BPD patients versus otherwise similar healthy controls. RESULTS: In 6/8 studies of euthymic BPD patients and 5/5 studies of non-euthymic BPD patients, neurocognitive impairment was significantly associated with impaired psychosocial functioning, even after adjusting for residual mood symptoms and relevant demographic and clinical variables. Cognitive status was consistently assessed with standardized, performance-based neuropsychological tests, but functional status usually was based on subjective self-appraisals. Approximately 55% of BPD patients were unemployed. CONCLUSIONS: Available studies are limited by subjective assessments of functional status rather than objective, performance-based measures. Nevertheless, they support the hypothesis that enduring aspects of cognitive impairment found even in euthymic BPD patients are associated with inferior functioning. These findings encourage further studies with better assessment methods and greater rehabilitative efforts in BPD patients.