Risperidone is FDA-approved for the treatment of irritability in children with Autism Spectrum Disorders (ASD). Previously-published short-term treatment studies have suggested beneficial effects for core ASD symptoms.
Objectives:
This study capitalized on a life-course longitudinal study of children with ASD to examine the effect of risperidone on the course of core ASD symptoms over time.
Methods:
Parents of 200 children in the Washington University Sibling Study provided retrospective summaries of the interventions received by their ASD-affected children over the course of their clinical care. Yearly parent-report assessments using the Social Responsiveness Scale (SRS) were conducted over the course of the longitudinal study. Parents of 51 of the children reported that the child had received a trial of risperidone. Twenty-eight had at least two SRS assessments related to the course of risperidone treatment: 19 had baseline SRS assessments documented prior to initiation of treatment and at least one SRS assessment following initiation of treatment; 9 had no available baseline assessment but at least two SRS assessments recorded following initiation of risperidone treatment. Parents of 23 of the children reported that their children were improved on risperidone (mean age 6.4, SD 3.3; mean duration of treatment 52.8 months, SD 33.7). Parents of the other 5 subjects indicated that risperidone was ineffective or associated with unacceptable adverse effects (mean age 6.7, SD 3.7; mean duration of treatment 69.4, SD 32.2). Intra class correlation for serial assessments on the SRS during the course of risperidone treatment (i.e. test-retest reliability for the sample as a whole) was 0.91, p<0.00001.
Results:
Among children whose parents reported that risperidone treatment was sustained because it was beneficial, the mean change in total SRS score from baseline (prior to initiation of medication) to the latest available follow-up during the period of use was an increase of 14.9 points on total SRS score (SD 18.2). For children with more than one SRS report while on risperidone (n=19) the mean rate of change in SRS score during risperidone treatment was an increase of 3.4 points per year. There was no association of time-rated change in score with either age or severity of autistic impairment at the time of the earliest available SRS assessment. There were no significant time-rated improvements in any of the SRS sub scales. Parents’ narrative reports of improvement in their children related to reduced aggression, better attention, less anxiety, fewer mood swings, and better task focus. For the children whose parents reported a negative effect from treatment risperidone, SRS scores remained unchanged or worsened over the course of treatment.
Conclusions:
In this naturalistic longitudinal study, children affected by ASD whose parents reported benefit from long-term use of risperidone did not show evidence of improvement in core autistic symptomatology over time. Given cumulative risks of long-term use of atypical neuroleptics, these results underscore the importance of periodic re-evaluation of the magnitude of medication effect for children with ASD receiving neuroleptic treatment.