Comparison of cognitive functions between first- and multi-episode bipolar affective disorders

Background: Cognitive impairment has been commonly found in euthymic patients with bipolar affective disorder (BPAD). Information about onset and course of cognitive deficits is, however, scarce. This study examined the cognitive profile of patients following their first episode of BPAD to determine whether cognitive problems are present at such an early stage. Methods: Executive functions, memory, IQ, attention-concentration and perceptuomotor function were assessed in 16 euthymic patients with BPAD following their first episodes, and compared with a group of 30 euthymic patients with multiple episodes of BPAD and 20 normal controls. Comparisons were controlled for educational status, current IQ and residual symptoms. Results: First-episode patients were significantly impaired, compared to normal controls, on tests of executive function, sustained attention, perceptuomotor function and IQ. Additionally, their performance was significantly worse than patients with multi-episode BPAD on tests of executive functions, sustained attention and perceptuomotor function. Multi-episode patients had impaired memory, compared to normal controls, and performed poorly on a subtest of executive functions compared to first-episode patients. Limitations: Sample sizes were small, assessments cross-sectional; all confounds could not be controlled for. Conclusions: Widespread cognitive disturbances following the first episode of BPAD were found in this study. Whether these disturbances progress following repeated episodes was not entirely clear. Since cognitive impairment can have several adverse consequences for patients of BPAD in terms of disability, quality of life, outcome etc., this must remain a priority area for future research.