From the Guidelines
Risperidone is the most appropriate antipsychotic for patients with psychosis and concurrent Autism Spectrum Disorder (ASD), due to its efficacy in managing both psychotic symptoms and autism-related irritability, aggression, and repetitive behaviors, as well as its relatively favorable side effect profile 1.
Key Considerations
- The recommended starting dose of risperidone is low, typically 0.25-0.5 mg daily for adults, gradually titrating up to an effective dose, usually 1-3 mg daily divided into two doses.
- For children (5-16 years), starting doses should be even lower at 0.25 mg daily, with careful titration based on response and side effects.
- Aripiprazole is a good alternative, starting at 2-5 mg daily for adults and 2 mg daily for children, with typical effective doses of 5-15 mg daily.
Mechanism of Action
- Risperidone and aripiprazole work primarily by modulating dopamine and serotonin neurotransmission, which helps address the neurochemical imbalances underlying psychotic symptoms while also potentially improving some core ASD features.
Monitoring and Follow-up
- Close monitoring for metabolic side effects (weight gain, lipid abnormalities), extrapyramidal symptoms, and sedation is essential, with regular follow-up appointments recommended every 2-4 weeks during initial treatment.
- Lower doses are often effective in ASD populations, who may be more sensitive to both therapeutic effects and side effects of antipsychotics.
Clinical Guidelines
- The use of atypical antipsychotics, such as risperidone, is justified for the treatment of psychosis in individuals with ASD, due to their noted efficacy and side-effect profile in the adult literature 1.
- Clinical guidelines recommend that treatment should commence prior to the development of a crisis, such as self-harm, violence or aggression, and may be an appropriate alternative to in-patient admission 1.
From the Research
Antipsychotic Options for Patients with Psychosis and Autism Spectrum Disorder (ASD)
- Risperidone and aripiprazole are the only second-generation antipsychotic drugs that have shown to decrease disruptive behaviors in large-scale, controlled, double-blind studies for patients with ASD 2.
- Clozapine, a second-generation antipsychotic, has been found to be effective in reducing disruptive behaviors in patients with ASD who did not respond to first-line antipsychotic drugs, with a significant 2-fold decrease in the number of days with aggression 2.
- Aripiprazole and risperidone have been approved by the FDA for the treatment of autism spectrum disorders, and have been found to be effective in reducing symptoms of autism, including aggression and self-injurious behavior 3, 4.
Safety and Efficacy of Antipsychotics in Patients with ASD
- Atypical antipsychotics, including olanzapine, quetiapine, and risperidone, have been found to be effective in improving certain behavioral symptoms of autistic disorder, but are associated with potentially significant adverse effects, such as weight gain and sedation 4.
- A 52-week randomized, double-blind study found that olanzapine, quetiapine, and risperidone had similar rates of all-cause treatment discontinuation in patients with early psychosis, but differed in their side effect profiles 5.
- A study comparing the longer-term safety and effectiveness of four atypical antipsychotics (aripiprazole, olanzapine, quetiapine, and risperidone) in patients over 40 found a high discontinuation rate and a high incidence of metabolic syndrome and adverse events, suggesting caution in the use of these drugs in middle-aged and older patients 6.
Considerations for Treatment
- The choice of antipsychotic medication for patients with psychosis and ASD should be based on individual patient needs and medical history, as well as the potential risks and benefits of each medication 2, 3, 6, 4, 5.
- Clozapine may be considered for patients with ASD who have not responded to first-line antipsychotic drugs, but its use requires careful monitoring due to the risk of significant weight gain and other adverse effects 2.