Importance: Cognitive behavior therapy (CBT) among youth with obsessive-compulsive disorder (OCD) is effective, but many patients remain symptomatic after intervention. d-cycloserine, a partial agonist at the N-methyl-d-aspartate receptor in the amygdala, has been associated with enhanced CBT outcome for OCD among adults but requires evaluation among youth.
Objectives: To examine the relative efficacy of weight-adjusted d-cycloserine (25 or 50 mg) vs placebo augmentation of CBT for youth with OCD and to assess if concomitant antidepressant medication moderated effects.
Design, setting, and participants: In a placebo-controlled randomized clinical trial, 142 youths (age range, 7-17 years) enrolled between June 1, 2011, and January 30, 2015, at 2 academic health science centers (University of South Florida and Massachusetts General Hospital) with a primary diagnosis of OCD were randomized in a double-blind fashion to d-cycloserine plus CBT or placebo plus CBT. Intent-to-treat analysis was performed.
Interventions: Patients were randomly assigned in a 1:1 ratio to either 10 sessions of d-cycloserine plus CBT or placebo plus CBT. d-cycloserine (25 or 50 mg) or placebo was taken 1 hour before sessions 4 through 10.
Main outcomes and measures: Children's Yale-Brown Obsessive Compulsive Scale at randomization, biweekly, midtreatment, and posttreatment. Secondary outcomes included the Clinical Global Impressions-Severity or Clinical Global Impressions-Improvement, remission status, Children's Depression Rating Scale, Multidimensional Anxiety Scale for Children, and Children's Obsessive-Compulsive Impact Scale-Parent Version.
Results: The study cohort comprised 142 participants. Their mean (SD) age was 12.7 (2.9) years, and 53.5% (76 of 142) were female. A mixed-effects model using all available data indicated significant declines in the Children's Yale-Brown Obsessive Compulsive Scale total score and Clinical Global Impressions-Severity. No significant interaction between treatment group and changes in the Children's Yale-Brown Obsessive Compulsive Scale and Clinical Global Impressions-Severity indicated that the d-cycloserine plus CBT group and the placebo plus CBT group declined at similar rates per assessment point on the Children's Yale-Brown Obsessive Compulsive Scale total score (estimate, -2.31, 95% CI, -2.79 to -1.83 and estimate, -2.03, 95% CI, -2.47 to -1.58, respectively) and Clinical Global Impressions-Severity (estimate, -0.29, 95% CI, -0.35 to -0.22 and estimate, -0.23, 95% CI, -0.29 to -0.17, respectively). No group differences in secondary outcomes were present. Antidepressant medication use at baseline did not moderate changes for either group.
Conclusions and relevance: d-cycloserine augmentation of CBT did not confer additional benefit relative to placebo among youth with OCD. Other augmentation approaches should be examined to enhance outcome.
Trial registration: clinicaltrials.gov Identifier: NCT00864123.