Tenn. Code Ann. § 33-6-504: Persons who may file complaint for commitment under this part

The parent, legal guardian, legal custodian, conservator, spouse, or a responsible relative of the person alleged to be in need of care and treatment, a licensed physician, a licensed psychologist who meets the requirements of § 33-6-427(a) , a health or public welfare officer, an officer authorized to make arrests in the state, or the chief officer of a facility that the person is in, may file a complaint to require involuntary care and treatment of a person with mental illness or serious emotional disturbance under this part.