Long-term cost-effectiveness of cognitive behavioral therapy versus psychodynamic therapy in social anxiety disorder

BACKGROUND: To determine the cost-effectiveness of cognitive behavioral therapy (CBT) versus psychodynamic therapy (PDT) in the treatment of social anxiety disorder after a follow-up of 30 months from a societal perspective.

METHODS: This analysis was conducted alongside the multicenter SOPHO-NET trial; adults with a primary diagnosis of social anxiety disorder received CBT (n = 209) or PDT (n = 207). Data on health care utilization and productivity loss were collected at baseline, after 6 months (posttreatment), and three further follow-ups to calculate direct and indirect costs. Anxiety-free days (AFDs) calculated based on remission and response were used as measure of effect. The incremental cost-effectiveness ratio (ICER) was determined. Net benefit regressions, adjusted for comorbidities and baseline differences, were applied to derive cost-effectiveness acceptability curves.

RESULTS: In the descriptive analysis, the unadjusted ICER favored CBT over PDT and the adjusted analysis showed that CBT's cost-effectiveness relative to PDT depends on the willingness to pay (WTP) per AFD. As baseline costs differed substantially the unadjusted estimates might be deceptive. If additional WTPs for CBT of €0, €10, and €30 were assumed, the probability of CBT being cost-effective relative to PDT was 65, 83, and 96%. Direct costs increased compared to baseline across groups, whereas indirect costs did not change significantly. Results were sensitive to considered costs.

CONCLUSIONS: If the society is willing to pay ≥€30 per additional AFD, CBT can be considered cost-effective, relative to PDT, with certainty. To further increase the cost-effectiveness more knowledge regarding predictors of treatment outcome seems essential.