Dr. Katarzyna Wyka, Professor at the CUNY Graduate School of Public Health and Health Policy, and colleagues from around the globe conducted a systematic review and meta-analysis to evaluate whether D-cycloserine is superior to placebo in augmenting the effects of cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders. The findings were published in JAMA Psychiatry.
The objective of this study was to determine whether and under which conditions D-cycloserine augments the effects of exposure-based cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders. Another objective was to clarify whether D-cycloserine is superior to placebo in augmenting the effects of cognitive behavior therapy for anxiety, obsessive-compulsive, and posttraumatic stress disorders.
The research team searched PubMed, EMBASE, and PsycINFO from inception to February 10, 2016. They also checked the reference lists of previous reviews and meta-analyses and reports of randomized clinical trials. Studies were eligible for inclusion if they were (1) double-blind randomized clinical trials of D-cycloserine as an augmentation strategy for exposure-based cognitive behavior therapy and (2) conducted in humans diagnosed as having specific phobia, social anxiety disorder, panic disorder with or without agoraphobia, obsessive-compulsive disorder, or posttraumatic stress disorder.
Raw data were obtained from the authors and quality controlled. Data were ranked to ensure a consistent metric across studies (score range, 0-100). The team used a 3-level multilevel model nesting repeated measures of outcomes within participants, who were nested within studies. Individual participant data were obtained for 21 of 22 eligible trials, representing 1047 of 1073 eligible participants.
When controlling for antidepressant use, participants receiving D-cycloserine showed greater improvement from pretreatment to posttreatment but not from pretreatment to midtreatment or from pretreatment to follow-up. Additional analyses showed that participants assigned to D-cycloserine were associated with lower symptom severity than those assigned to placebo at posttreatment and at follow-up. Antidepressants did not moderate the effects of D-cycloserine. None of the prespecified patient-level or study-level moderators was associated with outcomes.
The research team concluded that D-cycloserine is associated with a small augmentation effect on exposure-based therapy.