What do childhood attention deficit/hyperactivity symptoms in depressed adults tell us about the bipolar spectrum?

Depressed adults with significant childhood ADHD symptoms had a specific pattern of their major depressive episode compared to depressed patients without such symptoms. Subjects with childhood ADHD symptoms were more likely to report lifetime symptoms of mania/hypomania and to have a parent with type I or II bipolar disorder. The developmental trajectories of familial risk for lifetime bipolar symptoms showed that parental bipolar disorder influenced lifetime bipolar symptoms both through a direct pathway and an indirect pathway involving childhood ADHD symptoms. Childhood ADHD and number of depressive symptoms both made direct contributions to lifetime bipolar symptoms.