And some persons with mental retardation also have a diagnosis of mental illness. Most psychiatric inpatient hospitals have units especially for these persons, since their mental retardation affects the way their mental illness manifests itself and is treated. Some medications that work well for persons of average intelligence do not work as well for persons with mental retardation.
These persons have unique needs, both medically and intellectually. Therapy methods change for these persons, therapy goals change, medication goals change -- everything changes. The one constant is the desire to make sure the person is stable and not apt to cause harm to self or others.