Background: There is a developing literature into Anger Management interventions for people with intellectual disability. While initial reports suggest that these interventions are effective there are few evaluations examining what aspects of the therapeutic process contribute to effectiveness. Method: Individuals with an intellectual disability and anger control difficulties who were referred to community psychology services were allocated to either experienced clinical psychologists or a less experienced assistant psychologist who followed the same intervention framework. Results: Significant reductions in self-reported anger intensity were reported; however, the group who were treated by more experienced therapists reported more change and more individuals reported clinically significant change. Conclusions: While effective change was reported by both groups, these results suggest that clinical experience and training may be an important variable in determining the magnitude of change. This has implications for the design of intellectual disability mental health services.
