Minocycline as Adjunctive Treatment to Risperidone in Children with Autistic Disorder: A Randomized, Double-Blind Placebo-Controlled Trial

Objective: This is an investigation of minocycline efficacy and safety as an adjuvant to risperidone in management of children with autism. Methods: Forty-six children with diagnosis of autistic disorder, according to the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR) criteria and a score of >= 12 on the Aberrant Behavior Checklist-Community (ABC-C) irritability subscale, who were already drug-free for at least 6 months participated in a randomized controlled trial and underwent 10 weeks of treatment with either minocycline (50 mg twice per day) or placebo in addition to risperidone titrated up to 2 mg/day (based on bodyweight). Patients were evaluated using ABC-C at baseline and at weeks 5 and 10. Results: General linear model repeated measures showed significant effect for time x treatment interaction on the irritability [F(2, 88) = 3.94, p = 0.02] and hyperactivity/noncompliance [F(1.50, 66.05) = 7.92, p = 0.002], but not for lethargy/social withdrawal [F(1.61, 71.02) = 0.98, p = 0.36], stereotypic behavior [F(1.34, 58.80) = 1.55, p = 0.22], and inappropriate speech subscale scores [F(1.52, 66.88) = 1.15, p = 0.31]. By week 10, 21 (91.3%) patients in the minocycline group and 15 (65.5%) patients in the placebo group achieved at least partial response (p = 0.03). Frequencies of adverse events were not significantly different between groups. Conclusions: Minocycline seems to be a safe and effective adjuvant in management of patients with autistic disorder. Future studies with larger sample sizes, longer follow-ups, and inflammatory cytokine measurements are warranted to confirm these findings and provide insight into minocycline mechanism of action in autistic disorder.