Risperidone and Autism Ranking:

Current Research

Description of studies

We have identified more than 60* research papers on risperidone as an intervention for autistic people published in English-language, peer-reviewed journals.

These papers included more than 1,000 individuals aged from 3 to 48 years old, although the majority were primary school children or adolescents. These individuals included people with autistic disorder, Asperger syndrome and pervasive developmental disorder - not otherwise specified. 

The majority of studies were carried out by single research teams on single sites but some of the larger studies were carried out by several researchers on several sites. In the case of the series of studies carried out by the Research Units on Pediatric Psychopharmacology (RUPP) Autism Network we have identified more than 10 different papers. Some of these papers set out the rationale for the studies and explained the methodologies that would be used. Some of these papers reported on different parts of the studies (which included several controlled trials and several open trials). Some of the papers investigated the effects of risperidone on specific issues (such as adaptive behaviours, social communication and social interaction or repetitive and restricted behaviours). Some of the papers evaluated whether risperidone caused specific adverse effects (such as weight gain, somnolence and raised serum prolactin levels).

The length of treatment described in the papers we identified varied between six weeks and three years, although in most cases the treatment lasted between six to eight weeks. The dosage of risperidone varied from 0.75 mg per day to 3.5 mg per day, with younger children receiving smaller doses than adolescents and adults. In most cases, risperidone was started at a low dose and gradually increased to a higher maximum dose. 

Approximately half of the studies used a group design (usually comparing a group of people receiving risperidone to a different group receiving a placebo). Approximately half of the studies used singe case designs (usually in the form of an open trial of risperidone within a single group). 

A minority of the group studies compared risperidone with other antipsychotics (such as aripiprazole or haloperidol) or with other types of medication (such as buspirone or memantine). One of the studies compared low dose risperidone against high dose risperidone. Two of the studies compared risperidone combined with a parent training programme against risperidone alone.

*Please note: we have not included studies with fewer than three autistic participants and we have not included studies which combined risperidone with one or more other substances (including other medications or dietary supplements).  We have also not included any of the papers from the Research Units on Paediatric Psychopharmacology Autism Network studies where these did not measure the efficacy or otherwise of risperidone.

Outcomes from studies

• Most of the studies (such as Boon-Yasidhi et al, 2002) found that risperidone was effective in reducing irritable behaviour  such as aggression, self-injurious behaviours and sudden mood changes in some autistic people.
• Some of the studies (such as Williams et al, 2006) found that risperidone was effective in increasing adaptive behaviours in a range of areas, including communication, daily living skills, and socialisation in some autistic children and young people.
• The single study (Kent et al, 2013) which compared low dose risperidone (0.125-0.175 mg/day ) against high dose risperidone (0.5–3 mg/day) found that the high dose was more effective in reducing irritability in children and young people with autistic disorder, although the high dose also led to more frequent side effects.
• The studies which compared risperidone with aripiprazole (such as Ghanizadeh et al, 2014) found that these two antipsychotics were equally effective in treating irritability in autistic children.
• Most of the studies which compared risperidone with the older types of antipsychotics (such as haloperidol) or with other types of medication (such as buspirone) found that risperidone was more effective than the other medications.
• There was a single study (Nikvarz et al, 2017) which found that memantine was almost as effective as risperidone in reducing a range of symptoms in autistic children and young people.
• There was a single study (Tyrer et al, 2008) which found that a placebo was more effective than either risperidone or haloperidol in reducing challenging behaviour in patients with a learning disability (some of whom were autistic).
• The initial study which compared risperidone combined with a parent training programme against risperidone alone (RUPP AN, 2009) found that the combined package was more effective. However the follow up study (Arnold et al, 2012) found that the combined package was no more or less effective than risperidone alone.
• Many of the studies reported significant adverse effects. For example, the Research Units on Paediatric Psychopharmacology Autism Network studies reported a range of adverse side effects including weight gain, increased appetite, fatigue, drowsiness, dizziness and drooling. 

Updated

17 Jun 2022

Last Review

01 Jul 2018

Next Review

01 Jul 2024