Increasing positive outlook partially mediates the effect of empirically supported treatments on depression symptoms among adolescents

Among adolescents there is evidence that cognitive change partially mediates the effect of cognitive behavioral therapy (CBT) on depression outcome. However, prior studies have been limited by small samples, narrow measures of cognition, and failure to compare cognitive change following CBT to cognitive change following antidepressant medication. This study examined whether change in four cognitive constructs (cognitive distortions, cognitive avoidance, positive outlook, and solution-focused thinking) mediated change in depression severity in a sample of 291 adolescents who participated in the Treatment for Adolescents with Depression Study (TADS). TADS assessed the effects of CBT, fluoxetine, and their combination on depression severity. All three treatments were associated with change in the cognitive constructs and combination treatment produced the greatest change. Furthermore, change in the cognitive constructs partially mediated change in depression severity within all three treatments. Results implicated positive outlook as the construct most associated with change in depression severity over 36 weeks.