Is risperidone effective in reducing challenging behaviours in individuals with intellectual disabilities after 1 year or longer use? A placebo-controlled, randomised, double-blind discontinuation study

Background Many people with intellectual disabilities use risperidone long term for the management of challenging behaviours, despite its limited proof of effectiveness and its clear association with adverse events. Therefore, this study aimed to investigate the effectiveness of ongoing treatment with risperidone in reducing challenging behaviours versus controlled discontinuation on behaviour and health parameters. Method This was a placebo-controlled, double-blind, randomised discontinuation trial of risperidone. In the discontinuation group, risperidone was gradually replaced by a placebo over 14 weeks, while the control group maintained their existing dosage. Eight weeks after discontinuation, behaviour (as measured by the 'Aberrant Behavior Checklist') and health parameters (dyskinesia, akathisia, parkinsonism, weight, waist circumference, sedation and laboratory outcomes) were compared in both groups. Results A total of 25 participants were included in the trial, of which 11 were randomised into the discontinuation group and 14 were randomised into the continued treatment group. In the discontinuation group, 82% completely withdrew from risperidone. There was no significant change in irritability, compared with the continuation group, although there was a Group*Time effects on stereotypical behaviour in favour of the continuation group. Significant Group*Time effects were also found for weight, waist, body mass index, prolactin levels and testosterone levels, with beneficial effects for the discontinuation group. Conclusion Discontinuation of long-term risperidone for reducing challenging behaviours is possible, without an increase in irritability. Discontinuation of risperidone may have beneficial effects on weight, waist circumference, prolactin levels and testosterone levels. The study suffered from difficulties in achieving the required sample size, which affected study power and generalizability.