Beware of Over-Interpreting Negative Trials

The report by Tyrer et al. (2008) raises questions about the fit between study aims and study design. The study randomly assigned adults with intellectual disability to either risperidone (N = 29), haloperidol (N = 28) or placebo (N = 29) under double blind conditions. The primary target of treatment was aggressive behavior as measured by the Modified Overt Aggression Scale (MOAS) (Ratey and Gutheil 1991). The investigators note that aggressive behavior is a frequent problem in this population, that antipsychotic medications are commonly used in clinical practice and that the evidence supporting their use to treat aggression in this population is meager. The investigators conducted a pragmatic trial that included a relatively broad range of subjects across a range of settings. We agree with current practice guidelines that antipsychotic medications should not be administered without careful consideration of alternative treatments and documented evidence of recurring episodes of aggression (Rush and Frances 2000). It is not clear that the subjects in this study satisfied these clinical criteria. Therefore, the results of this study are difficult to interpret and fail to provide much direction for clinicians and families faced with trying to manage aggressive behavior in developmentally disabled adults. …