Sustained attention-deficit confirmed in euthymic bipolar disorder but not in first-degree relatives of bipolar patients or euthymic unipolar depression

A deficit of sustained attention is not present in patients with recurrent major depression tested during remission nor is it discriminable in the first-degree relatives of bipolar probands. Thus, the confirmed abnormality in euthymic bipolar patients may be acquired as a consequence of bipolar illness. However, future studies of relatives will require larger sample sizes to exclude or utilize small genetic effects.