Depression, the most common mental disorder, is frequently treated with cognitive therapy based on Beck's theory, which suggests that depressive cognitions (negative views of self, world, and future) affect psychosocial functioning. This study tested Beck's theory in depressed inpatients, previously hospitalized and nonhospitalized outpatients, and undiagnosed adults. Multiple regression indicated that negative views of self, world, and future explained a substantial part of psychosocial functioning in all 4 groups. In the 3 depressed groups, views of self and world had a greater impact on psychosocial functioning than did the view of the future, suggesting that interventions to build self-esteem and enhance self-control may be most effective in improving psychosocial functioning of depressed adults.