Adolescence is a time of emotional turmoil, mood lability, gloomy introspection, great drama and heightened sensitivity. It is a time of rebellion and behavioral experimentation. The physician's challenge is to identify depressive symptoms which may be superimposed on the backdrop of a more transient, but expected, developmental storm.

Diagnosis, therefore, must rely not only on a formal clinical interview but on information provided by collaterals, including parents, teachers and community advisors. The patient's premorbid personality must be taken into account, as well as any obvious or subtle stress or trauma that may have preceded the clinical state. The therapeutic alliance is very important since the adolescent will not usually readily share his/her feelings with an adult stranger unless trust and rapport are established.

Confidentiality must be assured, but not to the point that the parents - who are often essential allies in treatment - are wholly excluded. Diagnosis may require more than one interview and is not a process that can be rushed. Inquire directly about possible suicidal ideation. 

(Lewinsohn, P, Gregory, M, Clark, N, et al: Major depression in community adolescents: Age, episode duration, and time of recurrence. J Am Acad Child Adolesc Psychiatry 33(6):809,1994).