Okla. Stat. tit. 43A, § 43A-11-102
Legislative findings
A. The Legislature finds that all competent persons have the
fundamental right to control decisions relating to their own mental
health treatment, including the decision to accept mental health
treatment.
B. A capable adult may make an advance directive of mental
health treatment preferences or instruction which may include, but
is not limited to, consent to mental health treatment.