Psychometric properties of the Children's Scale of Hostility and Aggression: Reactive/Proactive (C-SHARP).

Although often lacking "malice", aggression is fairly common in children with intellectual or developmental disability (I/DD). Despite this, there are no scales available that are appropriate for an in-depth analysis of aggressive behavior in this population. Such scales are needed for the study of aggressive behavior, which is a common target symptom in clinical trials. We assessed the reliability and validity of the Children's Scale of Hostility and Aggression: Reactive/Proactive (C-SHARP), a new aggression scale created for children with I/DD. Data are presented from a survey of 365 children with I/DD aged 3-21 years. Interrater reliability was very high for the Problem Scale, which characterizes type of aggression. Reliability was lower but largely acceptable for the Provocation Scale, which assesses motivation. Validity of the Problem Scale was supported by expected differences in children with autism, Down syndrome, comorbid disruptive behavior disorders (DBDs) and ADHD. The Provocation Scale, which categorizes behavior as proactive or reactive, showed expected differences in children with DBD, but was less effective in those with ADHD. The C-SHARP appears to have fundamentally sound psychometric characteristics, although more research is needed.