A California law, found in Probate Code sections 810 through 813, designed to protect the rights of individuals by establishing specific legal standards and procedural safeguards for determining mental capacity (competence) in various legal contexts. The DPCDA ensures fairness when a person’s ability to make decisions or be held responsible for their actions is questioned. It applies to determinations of capacity related to executing wills, trusts, contracts, powers of attorney, advance health care directives, managing finances, consenting to medical treatment, and eligibility for conservatorship.