The applicability of the Dexamethasone Suppression Test (DST) with 39 mentally retarded individuals was examined. Subjects were assigned to one of three groups based upon the presence of zero, one, or two (or more) primary behaviors: unprovoked aggressive/assaultive behavior, self-injurious behavior, and severely withdrawn behavior. Chi-square analysis revealed that individuals exhibiting two or more of these types of behavior were more likely to obtain a positive DST result than were individuals exhibiting only one behavior. Results support the hypothesis that retarded persons can become depressed (as defined by the DST) and may express the depression through these behaviors. Furthermore, these results suggest that the current diagnostic criteria for depression in the retarded population need to be revised.