The Cognitive Therapy Scale and Cognitive Therapy Scale-Revised as Measures of Therapist Competence in Cognitive Behavior Therapy for Depression: Relations with Short and Long Term Outcome

Abstract

Therapist competence is an important factor in treatment integrity. This study reports on a direct comparison of the original Cognitive Therapy Scale (CTS) with the revised version, the Cognitive Therapy Scale-Revised (CTS-R), as observational instruments designed to evaluate therapist competence in a completed trial of Cognitive Behavior Therapy (CBT) for depression. Treatment sessions (N = 94) from 50 depressed participants (M age = 39.2 years, 76% female, with an average of 5.9 depressive episodes) were evaluated on the CTS and CTS-R by trained independent observers who were blind to treatment outcome, as well as to subject, and session numbers. A comprehensive training program and inter-rater reliability monitoring protocol were employed. Two models were used to compare CTS and CTS-R in relation to change in depression symptoms at termination, 12 and 24 month follow-up while controlling for pre-treatment depression levels and working alliance. Both the CTS and CTS-R demonstrated comparable internal reliability, interrater reliability, and when assessed in early treatment phase, both predicted a statistically significant reduction in depressive symptomatology at termination. No significant competence-outcome relations were detected with late CTS and CTS-R ratings, and the significant positive interaction terms indicated relations with depressive symptomatology were not maintained at follow-up. Given these findings, we encourage future research to examine specific competence domains and “therapist drift” with an increased number of session assessments.