The bio-behavioral methods proposed for use in this evaluation have been previously used to stratify and match treatments for self-injurious behavior in adults with developmental disabilities (Mace & Mauk, 1995), identify specific treatment effects of methylphenidate in children with ADHD (Northup & Gully, 2001), and more recently in evaluating the specificity of risperidone's effects on destructive behaviors in individuals with autism (Crosland, et al, 2003).