Division (A) & (B) of section 4757.01 define:

(A) "Practice of professional counseling"; means rendering or offering to render to individuals, groups, organizations or the general public a counseling service involving the application of clinical counseling principles, methods or procedures to assist individuals in achieving more effective personal, social, educational or career development and adjustment, including the diagnosis and treatment of mental and emotional disorders.

(B) "Clinical counseling principles, methods, or procedures" means an approach to counseling that emphasizes the counselor's role in systematically assisting clients through all of the following: assessing and analyzing background and current information, diagnosing mental and emotional disorders, exploring possible solutions and developing and providing a treatment plan for mental and emotional adjustment or development. "Clinical counseling principles, methods or procedures" includes at least counseling, appraisal, consulting and referral.

Section 4757.21 of the Revised Code states: Counselor may diagnose and treat mental and emotional disorders. A person licensed under this chapter to practice as a professional clinical counselor or a professional counselor may diagnose and treat mental and emotional disorders, except that a professional counselor may do so only under the supervision of a psychologist, psychiatrist, professional clinical counselor, independent marriage and family therapist, or independent social worker. A professional clinical counselor or professional counselor may engage in the private practice of professional counseling as an individual practitioner or as a member of a partnership or group practice.