A clinical diagnosis of major depressive disorder is rendered by an examining physician at each evaluation. The diagnosis is based on criteria of the Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition, Revised (DSM-III-R), clinical interview with the participant, and review of responses to a series of questions adapted from the Diagnostic Interview Schedule. The clinician is first presented with an algorithmic diagnosis and has the ability to modify if necessary.

Note: Most RADC publications have analyzed depressive symptoms using a 10-item version of the Center for Epidemiologic Studies Depression (CES-D) scale.