The effects of acute serotonin challenge on executive planning in patients with obsessive-compulsive disorder (OCD), their first-degree relatives, and healthy controls.

Our findings are consistent with a view that there is impaired executive planning in OCD and that this constitutes a behavioural endophenotype. In patients with OCD, but not in relatives, acute SSRI administration ameliorated this deficit. Further investigation is needed to understand common and differential involvement of neurochemical systems in patients with OCD and their relatives.