OBJECTIVES: It has been reported that one of the core features in patients with bipolar disorder II (BD II) is increased impulsivity. The aim of this study was to investigate whether patients with BD II showed decreased activation in the dorsal anterior cingulate cortex (dACC) as compared to healthy controls when performing a task sensitive to impulsivity.

METHODS: Twenty-seven BD II patients and 28 healthy controls performed a Go/No-go task during a functional magnetic resonance imaging (fMRI) session. Eleven of the patients were unmedicated, and possible group differences between medicated and unmedicated patients were also assessed. Results: The groups did not differ in behavioral performance on the Go/No-go task. Both BD II subjects and healthy controls demonstrated dACC activity during the task, and analyses revealed no statistically significant group differences. Medicated and unmedicated patients also did not differ in the degree of fMRI activation.

CONCLUSIONS: These findings do not support the hypothesis of abnormal dACC activity during a Go/No-go task in BD II patients.