Tenn. Code § 33-1-201
The department serves as the state's mental health and developmental disabilities authority and is responsible for system planning, setting policy and quality standards, system monitoring and evaluation, disseminating public information and advocacy for persons of all ages who have mental illness, serious emotional disturbance, or developmental disabilities. It is the policy of the state to plan on the basis of and to promote the use of private and public service providers, without regard for funding source, to achieve outcomes and accomplishments that create opportunities for service recipients and potential service recipients to have the greatest possible control of their lives in the least restrictive environment that is appropriate for each person. The department shall plan for and promote the availability of a comprehensive array of high quality prevention, early intervention, treatment, and habilitation services and supports based on the needs and choices of service recipients and families served. The department shall include service recipients and members of service recipients' families in planning, developing, and monitoring the service systems.
T.C.A. § 33-1-201