A pilot study of D-cycloserine in subjects with autistic disorder.

OBJECTIVE The authors assessed the effects of D-cycloserine on the core symptom of social impairment in subjects with autism. METHOD Following a 2-week, single-blind placebo lead-in phase, drug-free subjects with autistic disorder were administered three different doses of D-cycloserine during each of three 2-week periods. Measures used for subject ratings included the Clinical Global Impression (CGI) scale and Aberrant Behavior Checklist. RESULTS Significant improvement was found on the CGI and social withdrawal subscale of the Aberrant Behavior Checklist. d-Cycloserine was well tolerated at most of the doses used in this study. CONCLUSIONS In this pilot study, D-cycloserine treatment resulted in significant improvement in social withdrawal. Further controlled studies of D-cycloserine in autism appear warranted.