In addition to any other power authorized by law, the county governing authority may authorize the county board of health to enter into a contract with a regional or community mental health, mental retardation, and substance abuse service board created under Chapter 2 of Title 37 to provide certain mental health, mental retardation, and substance abuse services based on the contractual agreement between the parties. Further, a county governing authority may authorize a county board of health, wherever applicable, to serve as the community mental health, mental retardation, and substance abuse service board, provided that the county governing authority, the board of health, and any other affected county governing authority acts pursuant to subsection (e) of Code Section 37-2-6. In the event that the county governing authority exercises the authority granted by this Code section, Chapter 2 of Title 37, or Code Section 37-2-6, the county board of health shall appoint a director for mental health, mental retardation, and substance abuse or a supervisor of the specific service which is being provided by the county board of health, whichever is applicable, who shall meet the requirements established by the regional mental health, mental retardation, and substance abuse service board. The director for mental health, mental retardation, and substance abuse, or the service supervisor, shall not be required to be a physician and shall be a person other than the director of the county board of health appointed pursuant to Code Section 31-3-11. Further, such director for mental health, mental retardation, and substance abuse or such supervisor of the specific service shall report directly to the community service board or the county board of health, whichever is applicable, and shall have no formal reporting relationship with the director of the county board of health. If a county board of health exercises the authority granted pursuant to this Code section and Chapter 2 of Title 37 to serve as a community service board, the membership of the county board of health shall constitute the community service board and, at any time that such members are exercising duties and powers related to mental health, mental retardation, and substance abuse, the community service board shall be an independent agency and shall operate in accordance with the provisions of Title 37 as a community service board. Notwithstanding any provisions of law to the contrary, a community service board and a county board of health which have the same membership may contract with each other, provided that any such contract is approved by the appropriate regional board, as defined in Chapter 2 of Title 37, prior to adoption.