3H-imipramine binding in depressed elderly: relationship to family history and clinical response.

Platelet 3H-imipramine binding (Bmax) was determined in 34 elderly (mean age 64.8) unipolar depressed outpatients who were being treated with either nortriptyline or interpersonal psychotherapy for 10 to 16 weeks, and in nondepressed elderly controls. Bmax values were decreased in the depressed group. In addition, Bmax values were depressed further in subjects with a history of depression in first degree relatives. Good clinical response with either nortriptyline or psychotherapy was associated with lower Bmax compared to those subjects who had a poorer response to treatment. Treatment nonresponders and those with a negative family history of depression had Bmax values that were somewhat decreased but not significantly different from controls. This study extends to the elderly the potential applicability of platelet 3H-imipramine binding as a marker of depressive illness, and proposes a predictor for treatment response in elderly unipolar depressed patients.