Comparing Different Sequential Mediational Interpretations of Beck's Cognitive Model of Depression in Adolescents.

Depression is a developmental phenomenon with significantly increasing rates during adolescence. As Beck's cognitive model of depression has been commonly accepted to explain the development and maintenance of depression, it is crucial to understand how and when cognitive vulnerabilities predicted in this model begin to interact. Three sequential interpretations of this model were compared. The causal mediational interpretation identifies dysfunctional attitudes as most distal to depressive symptoms, followed by cognitive errors, cognitive triad, and negative automatic thoughts, with each construct successively more proximal to depressive symptoms. In the symptom model the causal chain is reversed, with depressive symptoms as the most distal construct, followed by negative automatic thoughts, the cognitive triad, cognitive errors, and then dysfunctional attitudes. The bidirectional model merges both interpretations in which the activation of cognitive constructs causes the development of depressive symptoms which in turn trigger and reinforce already existing dysfunctional attitudes. Further, while Beck's model of depression proposes full mediation, empirical studies identified repeatedly partial mediations. Thus, the causal meditational, the symptoms, and the bidirectional model were each tested as full and partial mediation models. Finally, sex differences in the associations between variables were studied. In the 3-wave longitudinal study, 518 high school students (62.7 % female, average age: 15.09 years) completed questionnaires measuring all mentioned elements of Beck's model. The bidirectional model with partial mediation fits the data best. Cognitive errors emerged as the main mediator in the bidirectional model with partial mediation and significant sex differences in the strengths of associations were identified. The findings demonstrate the relevance of adolescence as developmental period during which the examined associations develop into the network they form in adulthood. Further, psychological interventions focusing on cognitive errors promise to be most effective.