Section 21A. The center shall establish a continuing program of investigation and study of mental health, chronic pain and substance use disorders in the commonwealth. The investigation and study shall also include developing and defining criteria for health care services to be categorized as behavioral health services, with subcategories including, but not limited to: (i) mental health; (ii) substance use disorder; (iii) outpatient; (iv) inpatient; (v) services for children; (vi) services for adults; and (vii) provider type.