In the mid‑1800s, psychological practice was largely informal, and the notion of a client’s legal claim was virtually nonexistent. Early medical ethics codes began to articulate a duty of confidentiality, but enforcement was weak. The first explicit statutes—such as the 1900 U.S. law on mental health patient rights—started to formalize the therapist–client relationship, setting a precedent for future regulation.
The mid‑20th century saw landmark legislation, most notably the 1960s patient‑rights movements, which demanded transparency and autonomy. Subsequent legal milestones—such as the 1976 Health Insurance Portability and Accountability Act and the 1995 Mental Health Parity Act—expanded privacy protections and mandated equal coverage. Today, clients are empowered by state licensing boards, federal statutes, and court precedents that collectively enforce informed consent, record access, and the right to file grievances.