Dysthymic disorder is a chronic depressive condition with considerable psychosocial impairment. Even if DD patients respond to various antidepressant medications, there has been little systematic study on antidepressant-refractory DD. Only a few trials have evaluated the effects of treatment on psychosocial functioning of dysthymic patients. In this 3-month, open-label study, 60 outpatients with DSM-IV criteria for dysthymic disorder who failed to respond to 3-month treatment with paroxetine 20 mg/day were randomly assigned to treatment with paroxetine 40 mg/day or paroxetine 20 mg/day plus amisulpride 50 mg/day. The effects of the two treatments were assessed for both mood symptoms (21-item Hamilton Rating Scale for Depression, Montgomery-Asberg Depression Rating Scale, Clinical Global Impression, severity and improvement) and psychosocial outcomes (DSM-IV Global Assessment of Functioning, Social Adaptation Self-evaluation Scale). Analysis of variance on all rating scales showed that both treatments were effective over this observation period. Response and remission rates did not differ in the treatment groups. A significantly greater psychosocial improvement was observed in the group receiving combined treatment compared with patients receiving paroxetine alone. Both treatments appeared to be effective in our sample of dysthymic subjects. Combined treatment with paroxetine and amisulpride resulted in a better outcome in terms of social functioning.