Obsessive-compulsive disorder (OCD) is a debilitating psychiatric disorder with a lifetime prevalence of 1% to 2%,
1,2 often with onset in childhood.
3 Exposure and response prevention (ERP) and antidepressants are effective treatments,
4,5 but response is mixed, indicating a need to develop more effective strategies. Based on experimental animal studies demonstrating that D-cycloserine (DCS), a partial N-methyl-D-aspartate receptor agonist,
6,7 facilitates extinction learning, a number of human clinical trials have assessed whether ERP is augmented by DCS. While some early publications were promising,
8,9 more recent meta-analyses show only small augmentation of DCS vs placebo (effect size, 0.25)
10 and others no significant difference,
11-13 including no significant difference in several studies involving patients with OCD.
10,11,14-16 A study by Andersson et al
17 concluded that DCS did not augment the effects of cognitive behavioral therapy, but found that antidepressants may interact with DCS to block its facilitating effect on fear extinction.