Changes in affective and cognitive distortion symptoms of depression are reciprocally related during cognitive behavior therapy

We tested the predictions from Beck's cognitive theory that change in cognitive distortions precedes and predicts change in affective symptoms of depression, and his secondary prediction that change in affective symptoms precedes and predicts change in cognitive distortions during the course of cognitive behavior therapy (CBT; Beck, 1963). We used bivariate latent difference score modeling to examine change in affective and cognitive distortion symptoms of depression over time in a sample of 1402 outpatients who received naturalistic CBT in a private practice setting. Patients completed the Beck Depression Inventory (BDI) at each therapy session to monitor their progress in treatment. We selected items from the BDI to create measures of affective and cognitive distortion symptoms that allowed us to assess change in those phenomena over the course of treatment. We examined BDI data from up to 12 sessions of treatment for each patient. As predicted by Beck's theory, we found that change in cognitive distortion symptoms preceded and predicted change in affective symptoms of depression, and that change in affective symptoms preceded and predicted change in cognitive distortion symptoms. Both effects were small in size. These findings support the notion that change in affective and cognitive distortion symptoms of depression each precedes and predicts the other - that is, they are reciprocal in nature during cognitive behavior therapy. We discuss implications of our findings for the nature of the change process in CBT.