This paper discusses three functional classes of assessment of depression: (1) global measures for comparability; (2) specific measures of depression components; and (3) measures of model-related dimensions. Attempts at assessing depression in two psychotherapy studies are presented. This research has been organized around a model which assumes that depressed behavior can be seen as the result of a series of deficits in self-control. A behavioral self-control group therapy program, focusing successively on self-monitoring, self-evaluation and self-reinforcement behavior, was utilized. The studies demonstrate that a self-control program can produce significant improvement on global self-report measures and on certain measures of overt-motor activity level indicative of depression. There is further need for refinement of precise measures of the many specific behaviors which the term "depression" encompasses. (Author/JLL)