22. Intellectual Disability (Mental Retardation)

Summary

Intellectual disability, or intellectual developmental disorder, describes a heterogeneous condition affecting a diverse population, and drawing boundaries around the disorder, and naming it, has always been a challenge. And yet, as advances in our understanding mount, we are closer to the development of new therapeutics, and also have a growing appreciation for the important role that psychiatry can play in the understanding and care of persons with intellectual disability. This chapter begins with a brief consideration of definitions, assessment, and epidemiology, followed by a summary of the main etiological aspects, and the usefulness of behavioral phenotypes in diagnosis. The chief mental disorders occurring with intellectual disability are surveyed, including attention-deficit hyperactivity disorder (ADHD), oppositional defiant disorder/conduct disorder, impulse control disorder, post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), mood disorders, and psychosis. It is important that the child psychiatrist's approach to psychiatric and especially behavioral problems in patients with intellectual disability is primarily based on empirical data, experience, and clinical consensus. We review treatment of these comorbid conditions using psychosocial therapeutic approaches, medication approaches, and holistic or ecological approaches.