Section 16.03.09.700 - INPATIENT BEHAVIORAL HEALTH SERVICES: DEFINITIONS01.Freestanding Psychiatric Hospital. A hospital, nursing facility, or other institution of sixteen (16) beds or less that is primarily engaged in the diagnosis and treatment of mental diseases. The hospital is not considered freestanding if it shares a building or campus with another hospital, or is owned by another hospital.02.Hospital Psychiatric Unit. The psychiatric unit of a general hospital that furnishes inpatient care and treatment services for mental illness under a psychiatrist or other physician qualified to treat mental diseases.03.Institutions for Mental Disease (IMD). A hospital, nursing facility or other institution of seventeen (17) beds or more that is primarily engaged in providing diagnosis, treatment, or care of persons with mental diseases, including medical attention, nursing care, and related services. A specific licensure is not necessary to meet this definition. This definition does not apply to ICF/IIDs.04.Substance Use Disorder. A substance use disorder is evidenced by a cluster of cognitive, behavioral, and physiological symptoms indicating that the individual continues using a substance despite significant substance-related problems. A diagnosis of a substance use disorder is based on a pathological pattern of behaviors related to use of the substance and the current DSM.Idaho Admin. Code r. 16.03.09.700