Naltrexone in young autistic children: replication study and learning measures.

OBJECTIVE: This study expanded upon previous work on naltrexone efficacy and safety in young autistic children and assessed performance on learning measures.

METHOD: Eleven children with autistic disorder, aged 3.0 to 8.3 years, were studied in home, school, and outpatient laboratory, bringing to 24 the combined study sample. Naltrexone, 1.0 mg/kg, was given daily in a randomized, double-blind, crossover design. Dependent measures were parent and teacher Clinical Global Impressions (CGI) and Naltrexone Side Effects Rating Scale (SE), Conners Parent Impulsivity/Hyperactivity Factor, Teacher Hyperactivity Factor, laboratory CGI, and analysis of videotaped behavior. Learning measures were the Early Intervention Developmental Profile-Language and paired-associate learning.

RESULTS: Comparisons between naltrexone and baseline, but not naltrexone and placebo, on parent and teacher ratings showed statistical significance. Three of 11 subjects improved in two or more settings. Side effects were mild. Administering naltrexone was a challenge. The combined study sample showed improvement on all parent measures and on Teacher CGI and SE-Restlessness compared with baseline and placebo. Eleven of the 24 children improved in two or more settings. Scores on learning measures did not change across conditions.

CONCLUSIONS: Naltrexone was associated with modest improvement of behavior in 11 of 24 children, but learning did not improve.