Naltrexone in autistic children: a double-blind and placebo-controlled study.

A double-blind, placebo-controlled study was designed to assess critically the effects of naltrexone on behavioral symptoms and learning in autistic children, and its safety. This is a preliminary report on 18 children, ages 3.08 to 7.99 years, who completed this ongoing study. Subjects were randomly assigned to naltrexone or placebo and received daily doses over a period of 21 days. Naltrexone was superior to placebo according to blind Clinical Global Consensus Ratings (unpublished scale). However, other behavioral rating measures did not confirm this result. There was only a suggestion that naltrexone reduced fidgety and hyperactive behavior and tended to alleviate overall symptomatology in older children. Naltrexone did not appear to affect discrimination learning. Results are preliminary and, owing to the small sample size, can be considered only suggestive until this study is completed or replication is obtained from independent research.