Duration of illness prior to hospitalization (onset) in the affective disorders.

Onset defined as duration of illness prior to index admission was studied in manic and unipolar depressive patients. The manic patients were far more likely to have an acute onset when defined in this way. Of considerable interest is the fact that depression spectrum disease patients, i.e. those patients with a family history of alcoholism in a first-degree relative, were much less likely than other depressive patients to have an acute onset of their illness. In this case, the acute onset was defined as having occurred within 1 month of hospitalization.