Dysthymia in the Offspring of Parents With Primary Unipolar Affective Disorder

This study examined whether there is a familial relation between primary early-onset dysthymia and major affective disorder. In addition, it explored the prevalence of other forms of psychopathology and social impairment in the adolescent and young adult offspring of patients with primary unipolar affective disorder. Subjects included 47 offspring of patients with primary unipolar depression, 33 offspring of patients with chronic orthopedic and rheumatological conditions, and 38 offspring of randomly selected community controls with no personal or family history of psychiatric disorder. All offspring received structured diagnostic interviews. Diagnoses were derived blind to parental group by using multiple sets of diagnostic criteria. The offspring of unipolar patients exhibited significantly higher rates of affective disorder, major depression, and dysthymia than did the offspring of medical and normal controls. The groups did not differ on rates of nonaffective disorders. Parental characteristics associated with dysthymia in offspring included chronic depression, age of onset of major depression, number of hospitalizations, and multiple family members with major affective illness. These results support the view that at least some forms of early-onset dysthymia are variants of major affective illness.