- Upon recommendation of then-Governor Frank Clement, the Tennessee General Assembly created the Department of Mental Health on March 13, 1953, to provide services to people with mental illness and mental retardation.
- In 1973, under the Comprehensive Alcohol and Drug Treatment Act, the General Assembly gave the Department responsibility for developing programs for treating and preventing alcohol and drug abuse. In July 1991, the Division of Alcohol and Drug Abuse Services was transferred to the Department of Health; then, in February 2007, it was transferred back to TDMH.
- Beginning in 1978, the Department was charged with licensing facilities that provide services to people with mental retardation, mental illness, and alcohol and drug abuse. The responsibility for management and operation of the Division of Mental Retardation Services was transferred to the Department of Finance and Administration by executive order in 2002.
- The Department’s name was changed to the Tennessee Department of Mental Health and Developmental Disabilities in 2000 as a result of a comprehensive revision of the mental health and developmental disability law. The revision also expanded the Department’s licensure authority from only facilities or agencies to include services, effective March 1, 2001. The revision of the law expanded eligibility for direct services to persons with developmental disabilities, other than mental retardation, beginning March 1, 2002. In 2003, the department celebrated its 50th anniversary.
- On January 15, 2011, the Department’s name was changed to the Tennessee Department of Mental Health as the responsibility for Developmental Disabilities was transferred to the newly created Department of Intellectual and Developmental Disabilities.
- Then, on July 1, 2012, the Department’s name was changed to the Tennessee Department of Mental Health and Substance Abuse Services.