42 CFR § 482.60 - Special provisions applying to psychiatric hospitals.
Psychiatric hospital must -
(a) Be primarily engaged in providing, by or under the supervision of a doctor of medicine or osteopathy, psychiatric services for the diagnosis and treatment of mentally ill persons;
(c) Maintain clinical records on all patients, including records sufficient to permit CMS to determine the degree and intensity of treatment furnished to Medicare beneficiaries, as specified in § 482.61; and
(d) Meet the staffing requirements specified in § 482.62.