Tenn. Code § 33-6-421
The chief officer shall file with the court, by the time of the probable cause hearing, certificates of need for care and treatment from two (2) licensed physicians; one (1) licensed physician and one (1) psychologist qualified under § 33-6-427(a); or one (1) licensed physician and one (1) qualified advanced practice provider, as defined in § 33-6-407(a), who is not in a collaborating agreement with the licensed physician who signed the other certificate of need filed with the court as required by this section, certifying that the defendant satisfies the requirements of § 33-6-502(1)-(4), and certifying that if involuntary treatment is not continued, the defendant's condition resulting from mental illness or serious emotional disturbance is likely to deteriorate rapidly to the point that the defendant would again be admissible under § 33-6-403, and showing the factual foundation for the conclusions on each item of the certificates.
T.C.A. § 33-6-421