Two-year longitudinal study of post-stroke mood disorders: dynamic changes in correlates of depression at one and two years.

As part of a prospective study of 103 stroke patients, we have analyzed the relation between depression and associated variables at 3 months, 6 months, 1 year, and 2 years after stroke. At all intervals up to and including 1 year poststroke, patients with left hemisphere strokes showed a strong relation between severity of depression and distance of the lesion on computed tomography scan from the frontal pole. At 2 years poststroke, this relation was no longer significant. The correlation between depression and impairment in activities of daily living peaked at 6 months and thereafter fell but remained significant at 1 and 2 years poststroke. The correlation between depression and cognitive impairment and between depression and social functioning fluctuated--with most correlations at 1 and 2 years follow-up nonsignificant. Although the conclusions that can be drawn from this study are limited by the fact that less than half of the original patients were followed up at each time, these declining correlations between depression and associated variables at 1 and 2 years follow-up may reflect the natural course of major depression which spontaneously remits between 1 and 2 years after stroke. The persisting significant association of impairment in activities of daily living with depression may reflect the effect of severe depression in sustaining and possibly retarding recovery from physical impairment.