Now in its third edition, this high-quality, informative textbook presents intellectual disability and psychiatric presentation through the ages, to present a clear focus on issues relevant to psychiatric aspects for children and adults, at different stages of life. An ideal text for all psychiatrists, in training and in practice, this up-to-date, comprehensive guide to the understanding of intellectual disability features links to specific psychiatric competencies, vital for those undergoing training. Covering the breadth of psychological, service and biological factors affecting people with intellectual disability, this edition includes updates on a wide range of issues: from psychiatric diagnosis and management, through genetic causation, behaviour, health issues, mortality to delivery of services (historic and current). Key for multiple professional groups, and authored by leading specialists, this text provides the definitive collection of cutting-edge research on the psychiatry of intellectual disability.