What are the predictors of success in getting rid of obsessions and rituals?

A study that was published in the current issue of Psychotherapy and Psychosomatics describes the psychological predictors of completing psychotherapy successfully in patients with obsessions and rituals.

Cognitive-behavioral therapy consisting of exposure and response prevention (EX/RP) is an effective treatment for obsessive compulsive disorder (OCD). However, no prior study has systematically examined what predicts patient adherence to EX/RP procedures. A group of investigators examined potential predictors of patient adherence to EX/RP and whether patient adherence mediated the relationship between these predictors and post-treatment OCD severity.

The sample consisted of 28 adults (18–70 years old) with OCD who received EX/RP as part of a clinical trial. In brief, patients participated in 8 weeks of EX/RP that included 3 introductory sessions and 15 twice-weekly 90-minute exposure sessions following the guidelines of Kozak and Foa. Patient adherence was measured at each exposure session using the Patient EX/RP Adherence Scale (PEAS); it assessed the quantity and quality of between-session exposures and the degree of response prevention practiced for homework. OCD symptoms were rated by independent evaluators using the Yale- Brown Obsessive-Compulsive Scale (Y-BOCS).

Four factors hypothesized to affect cognitive-behavioral therapy adherence in other patient groups were examined: treatment expectancy using the Expectancy Questionnaire, therapeutic alliance using the Working Alliance Inventory – Self Report (WAI-SR), readiness for change using the University of Rhode Island Change Assessment (URICA), and readiness for treatment using the Readiness Ruler.

Investigators also examined baseline characteristics that predicted EX/RP outcome in prior OCD studies. These included depressive severity as measured by the 17-item Hamilton Depression Rating Scale, insight on the Brown Assessment of Beliefs Scale, quality of life as measured by the Quality of Life and Enjoyment Questionnaire, Axis I comorbidity using the SCID-I, total number of serotonin reuptake inhibitor trials, female gender, employment status, work impairment as measured by an item on the Sheehan Disability Scale, and hoarding subtype.

Therapeutic alliance (WAI-SR, beta = 0.53), treatment readiness (Readiness Ruler, beta =0.38), and hoarding status (beta = –0.26) all had significant (p<0.05) independent effects on patient adherence. Patient adherence also had a significant direct effect (beta = –0.57, p<0.01) on outcome and significantly mediated the impact of these other predictors on post-treatment OCD severity.

The effects for treatment expectancy and readiness to change (URICA) were not significant in these mediation analyses. Work impairment (Sheehan Disability Scale) was not significantly associated with patient adherence, although it directly predicted post-treatment OCD severity (0.40, p<0.01). This study has several limitations.

First, the sample was relatively small. Replication in larger samples is needed. Second, this sample was generally adherent to EX/RP treatment. Different factors might influence patient adherence in treatment-refractory patients.

Finally, patients were relatively free of depression and had good insight, limiting inferences that can be made about the impact of either on patient adherence. If these findings are replicated, future research should develop interventions to enhance therapeutic alliance and treatment readiness, deliver these interventions to those who show poor alliance or treatment readiness, and test whether this leads to improved patient adherence and thereby outcome, as these findings suggest.