Clinical Psychology Review, Vol. 18, No. 7, pp. 765–794, 1998 Copyright © 1998 Elsevier Science Ltd Printed in the USA. All rights reserved 0272-7358/98 $19.00 + .00 PII S0272-7358(98)00010-5 765 MAJOR DEPRESSIVE DISORDER IN OLDER ADOLESCENTS: PREVALENCE, RISK FACTORS, AND CLINICAL IMPLICATIONS Peter M. Lewinsohn, Paul Rohde, and John R. Seeley Oregon Research Institute ABSTRACT. In this article we summarize our current understanding of depression in older (14–18 years old) adolescents based on our program of research (the Oregon Adolescent Depres- sion Project). Specifically, we address the following factors regarding adolescent depression: (a) phenomenology (e.g., occurrence of specific symptoms, gender and age effects, community versus clinic samples); (b) epidemiology (e.g., prevalence, incidence, duration, onset age); (c) comorbid- ity with other mental and physical disorders; (d) psychosocial characteristics associated with be- ing, becoming, and having been depressed; (e) recommended methods of assessment and screen- ing; and (f) the efficacy of a treatment intervention developed for adolescent depression, the Adolescent Coping With Depression course. We conclude by providing a set of summary state- ments and recommendations for clinicians. © 1998 Elsevier Science Ltd IN THE PAST 25 years, substantial progress has been made toward furthering our un- derstanding of depression among adults. Much less is known, however, regarding de- pression in children and adolescents. Beginning in the 1970s, a number of research- ers (e.g., Albert & Beck, 1975; Carlson & Cantwell, 1979; Carlson & Strober, 1979; Cytryn & McKnew, 1972; Fleming, Offord, & Boyle, 1989; Kashani & Simonds, 1979; Kovacs, Feinberg, Crouse-Novack, Paulauskas, & Finkelstein, 1984; Orvaschel, Walsh- Allis, & Weijai, 1988; Poznanski & Zrull, 1970; Puig-Antich, 1982; Rutter, Izard, & Read, 1986) began to focus on affective disorders in children and adolescents, concluding that depressive disorders clearly occur during this time in the age span, are clinically debilitating, and are associated with numerous negative sequella including future psy- chopathology. Since the mid-1980s, our group at the Oregon Research Institute has been engaged in an extensive program of research on the epidemiology and treatment of adolescent depression. The goal of this article is to summarize our current under- standing of depression in adolescents based on this body of research, with a special em- phasis on the clinical implications of our findings. Many of the results we review have Correspondence should be addressed to Peter M. Lewinsohn, Oregon Research Institute, 1715 Franklin Blvd., Eugene, OR 97403-1983.