How can mental health in persons with an intellectual developmental disability be improved? The contributions provide an up-to-date overview on various topics related to mental health in these people. In addition to new diagnostic approaches, innovative therapy methods are presented. The aim is to promote treatment and support in clinical practice and to improve the quality of life. Readers from science and practice, as well as persons involved and their relatives, can expect well-founded knowledge about the latest developments and important suggestions from a wide range of topics, such as autism, Down syndrome, dementia, deafness, trauma, emotional development, sexuality, conflict management, drama therapy etc.