Neuro-cognitive functioning in unaffected siblings of patients with bipolar disorder: Comparison with bipolar patients and healthy controls

AIM: Neurocognitive tests can provide reliable endophenotypes for bipolar disorder (BD). The aim of this study was to compare the neurocognitive functioning of unaffected siblings of patients of bipolar affective disorder (BPAD) with that of patients with BD and a group of healthy controls. MATERIALS AND METHODS: A total of 20 unaffected siblings of patients with BD-I, 20 patients of BD-I who were currently in remission and a group of 20 healthy control subjects were assessed for neurocognitive functions using Wisconsin Card Sorting Test, Brief Visuospatial Memory Test-Revised, Hopkins Verbal Learning Test-Revised and Wechsler Adult Intelligence Scale Digit Symbol Test. RESULTS: Compared to healthy controls, unaffected siblings of patients with BD performed poorly on tests of verbal learning, but no significant differences were seen between the two groups for executive functions, visual learning and psychomotor speed, concentration and graphomotor abilities. Compared to unaffected siblings, patients with BD performed poorly on the tests of executive functions, visual memory, verbal memory, psychomotor speed, concentration, and graphomotor abilities. CONCLUSION: Verbal memory can serve as an endophenotype of bipolar disorder.