Executive functioning in familial bipolar I disorder patients and their unaffected relatives

Objective: To compare the executive function of patients with familial bipolar I disorder (BP-I) with a history of psychotic symptoms to their first-degree relatives and normal controls. Methods: Three domains of executive function: response inhibition, working memory, and cognitive set shifting were assessed in 44 familial patients with a lifetime diagnosis of BP-I who had experienced psychotic symptoms, 42 of their unaffected first-degree relatives, and 47 controls. Results: Bipolar disorder patients and their unaffected relatives had significantly worse scores for response inhibition compared to healthy controls. The groups did not differ in working memory or cognitive set shifting. Conclusions: Impairments in response inhibition are associated with both psychotic bipolar disorder and genetic liability for this illness. Our results indicate that deficits in this specific domain of executive functioning are a promising candidate endophenotype for psychotic bipolar disorder.