Neuropsychological function in unmedicated recurrent brief depression.

Background: Recurrent brief depression (RBD) is a mood disorder characterized by mild to severe depressive episodes lasting less than 2 weeks and occurring approximately once a month with complete recovery between episodes. The aim of this study was to describe neuropsychological impairments associated with RBD, relating cognitive performance to clinical features and comorbidity.

Methods: Forty-six ICD-10 defined RBD patients (mean age 33.8) and 24 matched controls were assessed on working memory/attention tasks, executive functions, verbal/visual memory, and psychomotor speed.

Results: Patients were significantly impaired across all domains of cognition except for verbal learning and non-semantic verbal fluency. Neuropsychological performance was not related to depression severity, duration of depressive episodes, interval duration, psychiatric or somatic comorbidity, or attributable to a general reduction in processing speed or effort. Patients reporting previous major depressive episodes were impaired on one measure of psychomotor speed. Previous episodes of hypomania were not related to neuropsychological performance.

Limitations: The relatively high number of self-referrals, high female-to-male ratio in the patient sample, and the relatively high level of education and intellectual capacity among participants may limit the possibility to generalize our results to the RBD population in general.

Conclusions: Unmedicated RBD patients demonstrate significant neuropsychological impairment that also may persist into euthymic states. Examining cognitive functions might be equally important in RBD as in major depression with consequences for functional diagnostics and treatment strategies.