Nothing in this part shall be construed as permitting any person licensed as an alcohol or drug abuse counselor to engage in the practice of medicine, or to engage in the practice of a licensed psychologist, licensed psychological examiner, licensed senior psychological examiner, certified psychological assistant, licensed social worker, licensed professional counselor, licensed marriage and family therapist, or psychiatric nurse. Persons licensed as alcohol and drug abuse counselors shall not be authorized by this part to dispense or prescribe drugs. Nothing in this part shall be construed to constrict or limit the practice of medicine, the certification and licensing of social workers, the licensing of nurses, the licensing of psychologists, or the licensing of professional counselors and marriage and family therapists. In addition, nothing in this part shall be construed to prevent qualified members of such professions from advertising that such persons diagnose and treat alcohol and drug disorders within the scope of their respective professions or from actually diagnosing and treating alcohol and drug disorders within the scope of their respective professions.