Neuropsychological performance among bipolar disorder patients, their unaffected first degree relatives and healthy controls

Bipolar disorder (BD) is a chronic brain illness with a relapsing and remitting course. Widespread neuropsychological deficits is a common feature of bipolar disorder. The aim of our study is to compare bipolar depressive and euthymic patients and their unaffected first degree relatives with healthy controls in terms of neuropsychological performance. Our assessment considers executive functions, working memory, attention, verbal learning, verbal fluency and memory. We hypothesised that that the patients would present poorer neurocognitive performance regardless of the state of illness compared to healthy controls and the unaffected first degree relatives who would perform worse than the controls but better than the patients. Depressive patients were expected to show poorer neurocognitive performance than euthymic patients.Thirty euthymic, 10 depressive patients with bipolar disorder, their fifteen unaffected first degree relatives and twenty six sex, age and education-wise matched healthy controls were enrolled in the study. Comprehensive neuropsychological battery was applied to all participants. Patient group was also given Hamilton Depression Rating Scale-17 and Young Mania Rating Scale. Kruskal-Wallis, Mann Whitney-U, and Spearman Corelation tests were used for statistical analysis.There was a significant difference between all groups in executive functions, verbal learning, working memory and category fluency tests. Patients in depressive episode performed poorer in verbal learning and memory tests than the euthymic patients, and poorer in verbal fluency, working memory and executive functions than healthy controls, whereas the euthymic patients had worse verbal learning, executive functioning and working memory performmance than the healthy controls. The first degree relatives did poorer in executive functions than healthy controls.Neurocognitive impairment exist at depressive and euthymic episodes of BD. It is also seen in healthy relatives of BD patients. Therefore, impairment in neurocognitive functions may be one of the endophenotypes for BD.