Aggression in its various forms (verbal, physical, property destruction and auto-aggressionor self-injurious behavior) is the most frequent cause for mental health appointmentsand assessments in patients with intellectual disabilities (ID) (Tenneijet al., 2009;Hurleyet al., 2007; Rueve & Welton, 2008; Silka & Hauser, 1997). Patients with IDexperience psychiatric and behavioral problems at three to six times the frequency of thegeneral population (Hardan & Sahl, 1997; Larsonet al., 2001). “Problem behavior” occursin approximately 50–60% of individuals with ID, and reported prevalence rates foraggression range widely from 2–40%, according to various reports (Clarket al., 1990;Deb & Fraser, 1994).