Two-year longitudinal study of poststroke mood disorders: diagnosis and outcome at one and two years.

As part of a prospective study of mood disorders in stroke patients, interviews were obtained from 37 patients at 1 year and 48 patients at 2 years follow-up. In-hospital evaluations for these 65 follow-up patients found that 9 patients (14%) had symptom clusters of major depression, 12 patients (18%) had symptom clusters of dysthymic or minor depression, and 44 patients (68%) did not meet the DSM III diagnostic criteria for depression. Although overall prevalence of depression did not change significantly over time, the prognosis for individual patients, depending on diagnostic group, was different. All of the follow-up patients with major depression in-hospital were improved by 2 years, with a significant reduction in their mean depression scores and improvement in their activities of daily living, whereas only 30% of follow-up patients with dysthymic depression improved by this time. There was no significant improvement in their mean depression scores or mean activities of daily living score. Of the patients followed up who were not depressed in-hospital, 34% had developed major or minor depression by 2 years, and their mean depression scores were significantly increased. These data suggest that the prevalence of depression among the follow-up patients remains high (between 30 and 40%) for the first 2 years after stroke, but that untreated poststroke major depression has a natural course of about 1-2 years, with associated improvement in activity of daily living scores, whereas the prognosis for poststroke dysthymic depression is frequently unfavorable and often persists for greater than 2 years.