Relations of Shared and Unique Components of Personality and Psychosocial Functioning to Depressive Symptoms

Consistent with theories of depression, several personality (e.g., high neuroticism, low extraversion) and psychosocial (e.g., interpersonal problems, cognitive content) variables predict depressive symptoms substantively. In this extended replication, we clarified whether 13 theoretically relevant personality and psychosocial variables were unique versus overlapping predictors of symptoms among 351 adult outpatients with recurrent major depressive disorder who received acute-phase cognitive therapy (CT). Using factor analysis and regression methods, we partitioned the measures' variance into general components common across the two types of measures (psychosocial and personality), within-type components shared only with other measures of the same type, and scale-specific components. From early to late in CT, and from late in CT through 8 months after response, the general components were the strongest (median r = .23)-and scale-specific components the weakest (median r = .01)-forward predictors of symptoms. We discuss implications for measurement and treatment of depression.