California Code, Probate Code - PROB § 4679

(a)(1) This chapter does not prohibit the execution of a voluntary standalone psychiatric advance directive.

(2) As used in this chapter, “psychiatric advance directive” means a legal document, executed on a voluntary basis by a person who has the capacity to make medical decisions and in accordance with the requirements for an advance health care directive in this division, that allows a person with mental illness to protect their autonomy and ability to direct their own care by documenting their preferences for treatment in advance of a mental health crisis.

(1) Research has demonstrated that the use of psychiatric advance directives improves collaboration, which improves outcomes, increases empowerment, and improves medication adherence.

(2) A psychiatric advance directive is most helpful when it includes reasons for preferring or opposing specific types of treatment.

(3) Mental health preferences that do not constitute health care instructions or decisions as defined in this part may provide valuable information to improve an individual's mental health care.