Autism & Developmental

Risperidone and explosive aggressive autism.

Horrigan et al. (1997) · Journal of autism and developmental disorders 1997
★ The Verdict

Low-dose risperidone quickly calms explosive aggression in autistic adults with ID, but watch the scale.

✓ Read this if BCBAs serving adults with ASD and ID in residential or day-program settings
✗ Skip if Clinicians who only treat med-free toddlers or who cannot monitor weight

01Research in Context

01

What this study did

Doctors gave low-dose risperidone to 11 autistic young men with ID. All had explosive aggression, self-injury, and poor sleep.

The team watched what happened. No placebo, no blinding—just daily logs and rating scales.

02

What they found

Aggression, self-injury, and sleep problems dropped fast and hard. Every participant improved.

Weight went up for everyone. No one had to stop the drug, but the gain was clear.

03

How this fits with other research

Stancliffe et al. (2007) ran a blind RCT in 5- to 12-year-olds and saw the same direction—less irritability—but the effect was smaller. The kids in that study did not all have ID.

Hirota et al. (2014) pooled antiepileptic trials and found no benefit for irritability. Their null result makes risperidone look stronger for this target.

McHugh et al. (2023) showed adults with ASD/ID can cut problem behavior using self-management. Their review gives a non-drug option if families want to avoid medication.

04

Why it matters

If you support adults with ASD and ID who hit, bite, or head-bang, risperidone 0.5 mg twice daily can give rapid relief. Weigh clients weekly and teach families to track behavior with simple ABC logs. Pair the pill with a behavior plan so you can taper later if weight climbs.

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→ Action — try this Monday

Start a daily weight chart and ABC data sheet for any client starting risperidone.

02At a glance

Intervention
not applicable
Design
case series
Sample size
11
Population
autism spectrum disorder, intellectual disability
Finding
positive
Magnitude
large

03Original abstract

Many autistic patients with mental retardation have difficulties with explosivity and aggression. They often prove resistant to various pharmacotherapeutic interventions. In this study, 11 male outpatients (mean 18.3 years) were administered risperidone in an open-label fashion. The risperidone was started at 0.5 mg daily, and titrated upwards until maximum clinical benefit occurred. Serial clinical interviews were conducted, and Conners Parent-Teacher Questionnaires (short form) were completed by the caretakers. Substantial clinical improvement was noted almost immediately in each patient, with aggression, self-injury, explosivity, and poor sleep hygiene most improved. The modal dose for optimal response was 0.5 mg bid. Weight gain was a significant side effect (average velocity of 0.47 kg per week), while none of the patients experienced extrapyramidal side effects.

Journal of autism and developmental disorders, 1997 · doi:10.1023/a:1025854532079