People with intellectual disabilities and mental health problems have the same right to high standards of assessment, treatment, and as good a quality of life as other people. Historically, the mental health problems of people with intellectual disabilities have had a low priority in health care systems around the world. Consequently the treatment facilities have been insufficient, the training of staff underdeveloped and the care offered far from the best to meet their mental health needs. This is further compounded by the fact that the mental health problems of people with intellectual disabilities are often very complex, difficult to diagnose and require specialist multiprofessional involvement.

The potential for comprehensive and effective care of people with intellectual disabilities and mental health problems has improved greatly in recent years with developments in the way that people with disabilities are viewed within society, increased understanding of psychological processes and with advances in neuroscience, genetics and neuro imaging. There are now more effective treatment methods including behaviour therapy, psychopharmacology, psychosocial interventions and psychotherapy.

This second edition of the book Psychiatric and Behavioural Disorders in Developmental Disabilities and Mental Retardation is fully revised and offers an up-to-date account in the field. In this edition we have replaced the term ‘mental retardation’ with ‘intellectual disabilities’ as the latter has gained widespread international recognition and acceptance.