Psychiatric disorders in individuals with co-occurring autism spectrum disorders (ASD) and intellectual disability (ID) are common, but diagnosis presents many challenges. The Psychopathology in Autism checklist (PAC) is among the very few instruments specifically developed for this group of individuals. The psychometric properties of the PAC…

Progress in clinical research and in empirically supported interventions in the area of psychopathology in intellectual disabilities (ID) depends on high-quality assessment instruments. To this end, psychometric properties of four instruments were examined: the "Aberrant Behavior Checklist" (ABC), the "Assessment of Dual…

Caretakers of adolescents and young adults with Down syndrome (DS) may report the onset of a depressive illness in previously mentally well individuals. However, the behavioral phenomenology of these conditions has not been well characterized. We ascertained a cohort of DS patient-subjects presenting to a specialty clinic with medical and/or…