POPULATION PREVALENCE OF PSYCHOPATHOLOGY IN CHILDREN AND ADOLESCENTS WITH INTELLECTUAL DISABILITY .1. RATIONALE AND METHODS

Our knowledge of the epidemiology of psychopathology in children and a dolescents with intellectual disability (ID) is hampered by a number o f factors. These include the relative scarcity of studies of children rather than adults, the study of non-epidemiological samples such as t hose in institutions or those attending psychiatric clinics, a lack of standardized methods of assessment of psychopathology, studies with n umbers too small to provide adequate confidence intervals around ident ified prevalence rates, insufficient detail concerning symptoms or syn dromes as well as disorder, and a lack of consistent data concerning t he effects of basic demographic variables such as age, sex and IQ. Des pite these limitations, it is clear that psychopathology is several ti mes more prevalent in children and adolescents with ID than in those w ithout this disability. This paper reviews findings from previous stud ies and describes the methodology of a new study using the Development al Behaviour Checklist.