Differential effects of sertraline and cognitive behavioural therapy on behavioural inhibition in patients with obsessive compulsive disorder.

Patients with obsessive compulsive disorder (OCD) randomised to sertraline, manualised cognitive behavioural therapy (CBT), or combination (sertraline + CBT), underwent cognitive assessment. Cognitive testing was conducted at baseline and at week 16. The stop signal reaction time task (SSRT) was used to evaluate motor impulsivity and attentional flexibility was evaluated using the intra/extra-dimensional set shifting task. Paired-samples t -tests or nonparametric variants were used to compare baseline and posttreatment scores within each treatment group. Forty-five patients were tested at baseline (sertraline n  = 14; CBT n  = 14; sertraline + CBT n  = 17) and 23 patients at week 16 (sertraline n  = 6; CBT n  = 7; sertraline + CBT n  = 10). The mean dosage of sertraline was numerically higher in those taking sertraline as a monotherapy (166.67 mg) compared with those taking sertraline in combination with CBT (100 mg). Analysis of pre-post treatment scores using an intent-to-treat-analysis found a significant reduction in the SSRT in those treated with sertraline, whilst there was no significant change on this task for those treated with CBT or the combination. This study found that motor inhibition improved significantly following sertraline monotherapy. Suboptimal sertraline dosing might explain the failure to detect an effect on motor inhibition in the group receiving combination of sertraline + CBT. Higher dose sertraline may have broader cognitive effects than CBT for OCD, motor impulsivity may have value as a measure of treatment outcome and, by extension, the SSRT could serve as a biomarker for personalising care.

Optimal treatment for obsessive compulsive disorder: a randomized controlled feasibility study of the clinical-effectiveness and cost-effectiveness of cognitive-behavioural therapy, selective serotonin reuptake inhibitors and their combination in the management of obsessive compulsive disorder.

Established treatments for obsessive compulsive disorder (OCD) include cognitive behaviour therapy (CBT) and selective serotonin reuptake inhibitor (SSRI) medication. Combined treatment may outperform monotherapy, but few studies have investigated this. A total of 49 community-based adults with OCD were randomly assigned to CBT, SSRI, or SSRI+CBT. Sertraline (50-200 mg/day) was given as the SSRI for 52 weeks. A 16-h-manualized individual CBT was delivered over 8 weeks with four follow-up sessions. Assessors were 'blinded' to treatment allocation. A preliminary health economic evaluation was conducted. At week 16, combined treatment (n=13) was associated with the largest improvement, sertraline (n=7) the next largest and CBT (n=9) the smallest on the observed case analysis. The effect size (Cohen's d) comparing the improvement in Yale Brown Obsessive Compulsive Scale on CBT versus combined treatment was -0.39 and versus sertraline was -0.27. Between 16 and 52 weeks, the greatest clinical improvement was seen with sertraline, but participant discontinuation prevented reliable analysis. Compared with sertraline, the mean costs were higher for CBT and for combined treatment. The mean Quality Adjusted Life Year scores for sertraline were 0.1823 (95% confidence interval: 0.0447-0.3199) greater than for CBT and 0.1135 (95% confidence interval: -0.0290-0.2560), greater than for combined treatment. Combined treatment appeared the most clinically effective option, especially over CBT, but the advantages over SSRI monotherapy were not sustained beyond 16 weeks. SSRI monotherapy was the most cost-effective. A definitive study can and should be conducted.