IMPORTANCE Disruptive behavior is common in children with autism spectrum disorder. Behavioral interventions are used to treat disruptive behavior but have not been evaluated in large-scale randomized trials. OBJECTIVE To evaluate the efficacy of parent training for children with autism spectrum disorder and disruptive behavior. DESIGN, SETTING, AND PARTICIPANTS This 24-week randomized trial compared parent training (n = 89) to parent education (n = 91

Objective Many children with Pervasive Developmental Disorders (PDDs) have serious, functionally-impairing behavioral problems. We tested whether Combined Treatment (COMB) with risperidone and parent training (PT) in behavior management is superior to Medication alone (MED) in improving severe behavioral problems in children with PDDs. Method This 24-week, three-site, randomized, parallel-groups clinical trial enrolled 124 children, aged 4 through 13 years, with PDDs, accompanied by frequent tantrums, self injury, and aggression. Children were randomized 3:2 to COMB (n= 75) or MED (n= 49). Participants received risperidone monotherapy from 0.5 to 3.5 mg/day (with switch to aripiprazole if risperidone was ineffective). Parents in COMB group (N=75; 60.5%) received a mean of 10.9 PT sessions. The primary measure of compliance was the Home Situations Questionnaire (HSQ) score. Results Primary: Intent-to-treat random effects regression showed that COMB was superior to MED on HSQ (p=.006) [effect size at Week 24 (d)= 0.34]. The HSQ score declined from 4.31 (±1.67) to 1.23 (±1.36) for COMB compared with 4.16 (±1.47) to 1.68 (±1.36) for MED. Secondary: Groups did not differ on Clinical Global Impressions–Improvement scores at end-point; compared with MED, COMB showed significant reductions on Aberrant Behavior Checklist Irritability (d=0.48; p= .01), Stereotypic Behavior (d=0.23; p= .04), and Hyperactivity/Noncompliance subscales (d=0.55; p= .04). Final risperidone mean dose for MED was 2.26 mg/day (0.071 mg/kg), compared to 1.98 mg/day for COMB (0.066 mg/kg) (p=.04). Conclusion Medication plus PT resulted in greater reduction of serious maladaptive behavior than medication alone in children with PDDs, with a lower risperidone dose.