The lists of associated symptoms included in the DSM-III, DSM-III-R, and DSM-IV criteria for dysthymic disorder have been criticized for lacking content and discriminant validity. The literature on the content and discriminant validity of dysthymic symptoms was reviewed and relevant data from the DSM-IV Mood Disorders Field Trial were presented. These data indicate that cognitive and social-motivational symptoms are much more characteristic of dysthymic disorder than are vegetative and psychomotor symptoms. In addition, subjects with major depressive disorder exhibit higher rates of most depressive symptoms than do subjects with dysthymic disorder, but there is little evidence of qualitative distinctions in symptomatology between these conditions. Finally, after taking course and exclusion criteria into account, variations in the symptom criteria do not have a major effect on case definition.