Paliperidone for irritability in adolescents and young adults with autistic disorder

Individuals with autistic disorder (autism) frequently exhibit significant irritability marked by severe tantrums, aggression, and self-injury. Despite advances in the treatment of this symptom domain in autism, there remains an ongoing need for more effective and better tolerated pharmacotherapies.

The aim of this study is to determine the effectiveness and tolerability of paliperidone for irritability in autism.

This is a prospective, 8-week open-label study of paliperidone in 25 adolescents and young adults with autism. Primary outcome measures included the Clinical Global Impressions-Improvement (CGI-I) Scale and the Irritability subscale of the Aberrant Behavior Checklist (ABC-I). Concomitant medications (except antipsychotics) were permitted if dosages were stable for ≥2 months.

Twenty-one (84 %) of 25 subjects ages 12-21 years (mean 15.3 years) responded to paliperidone, based on a CGI-I Scale score of 1 or 2 (very much or much improved) and ≥25 % improvement on the ABC-I. The mean final dosage of paliperidone was 7.1 mg/day (range 3-12 mg/day). Two subjects discontinued paliperidone prior to study completion (moderate sedation, n = 1; nonresponse, n = 1). Mild-to-moderate extrapyramidal symptoms were recorded in four subjects. A mean weight gain of 2.2 ± 2.6 kg (range -3.6 to +7.9 kg) was recorded. Mean age- and sex-normed body mass index increased from 23.6 to 24.2 (p ≤ 0.001). Mean serum prolactin increased from 5.3 to 41.4 ng/mL (p ≤ 0.0001).

Paliperidone treatment was associated with significant improvement in irritability and was generally well tolerated. Larger scale, placebo-controlled studies are needed to elucidate the efficacy and tolerability of paliperidone in this population.