It used to be thought that behaviour problems were a characteristic of intellectual disabilities themselves and that people with intellectual disabilities could not experience emotional distress. Contrary to previous beliefs, today we are aware that behavioral disorders and psychological disorders occur several times more often in people with intellectual disabilities than in the general population. The causes can be related to the biological, psychological and genetic characteristics of the child, but also to the inadequate environmental conditions in which these people live and grow up in. A more severe degree of intellectual difficulties also means more serious psychological disorders. Due to the ambiguities in the symptomatology and communication problems of these people, there are certain complications in the recognition, diagnosis and classification of their mental health disorders. In order to provide appropriate help and support and to raise the quality of life of mentally ill persons with ID, special knowledge and experience of clinicians in this field is required. The aim of this thesis is to provide an overview of the literature on mental health problems in people with intellectual disabilities. Through the integration of knowledge about intellectual disabilities, the importance of a holistic and multidisciplinary approach in the diagnosis and treatment of behavioral and psychological disorders of this population is emphasized. This review paper provides an insight into the causes and occurrence of psychopathology in people with IT, and it especially looks at the issue of organization of care and quality of life of these people. To understand the described problem, it is necessary to explain terms related to mental health and psychopathology.