Comparison of early and late onset dysthymia.

The present investigation compares early and late onset community dysthymia groups on insidious onset patterns, cognitive, coping, and symptom measures testing the assumption implicit in DSM-III-R that the two groups are qualitatively dissimilar. The results suggest that, regardless of age of onset, the groups did not differ except on some features of coping style. Homogeneity, not heterogeneity, was the predominant finding. The results call into question the DSM-III-R procedure for classifying dysthymia by age of onset, but also point to the need for additional research.