Psychometric Investigation of the CBT Adherence Measure

Patient adherence to cognitive behavioral therapy (CBT) has been shown to predict treatment outcome, yet current measures only assess between-­session treatment compliance (i.e.,homework completion) rather than within­-session compliance. The CBT Adherence Measure (CAM) is a nine­-item clinician rating of in-­session patient adherence and measures the extent to which the patient: 1) espouses and understands goals of the treatment, 2) provides a report of progress, 3) adheres to session agenda, 4) makes comments and statements that are appropriate to the topic, 5) cooperates with attempts to make cognitive change, 6) cooperates with attempts to make behavioral change, 7) makes appropriate reports of thoughts and feelings, 8) adheres to time requirements and 9) brings requested materials to the session. Ratings are made on a scale of 1 (not at all) to 4 (very much), and a total score consists of the average of all 9 items (range = 1­4). The aim of the current study was to determine the reliability and validity of the CAM in patients receiving CBT. The sample consisted of 26 participants with a primary diagnosis of obsessive­compulsive disorder (OCD; M age = 37.08, 65% female), and 29 participants with a primary diagnosis of hoarding disorder (HD; M age = 56.03, 82.8% female). The CAM was completed by a doctoral level clinician following a session of either in-person (HD group) or telephone­based (OCD group) CBT. Results indicate that the CAM is comprised of a single factor, accounting for 57% of the variance and internal consistency was excellent (α = .90). Concurrent validity was demonstrated in the OCD group by calculating correlation coefficients at each of the 9 treatment sessions. The CAM showed good concurrent validity with other within­session measures, such as clinician­rated effort ratings (r = .55 ­.86). Significant correlations with measures of between­session compliance, such as clinician­rated homework compliance (r = .56 ­ .87) and the Patient Exposure/Response Prevention Adherence Scale (PEAS; r = .81­.83) were also found, however no significant correlations were found for other measures. Interrater reliability was assessed in the HD group only and was high (ICC = 0.91). In the OCD group, the CAM correlated significantly with pre­ to post­treatment reduction in both clinician-­rated (r = .60) and patient­-rated (r = .59) Yale­-Brown Obsessive-­Compulsive Scale scores. Additionally, the CAM was significantly negatively correlated with symptom improvement on the Clinician Global Impression Scale (CGI­I; r = ­0.89), indicating a relationship between better within-­session adherence and clinical improvement. The OCD group (M = 2.39, SD = .62) scored significantly higher than did the HD group (M = 2.95, SD = .68) on the CAM, t(41) = ­2.83), p = <.01, indicating better within­session treatment compliance. These preliminary results suggest that the CAM is a reliable and valid measure of within-­session adherence to CBT. Inconsistent correlations between the CAM and measures of between­-session compliance emphasize the need for measuring both domains of patient adherence. Such information is important for understanding mechanisms of change in CBT, and could be used by clinicians to inform decisions regarding personalization of treatment.