MO Rev Stat § 337.015 (2021)
2021 Missouri Revised Statutes|Title XXII - Occupations and Professions|Chapter 337 - Psychologists — Professional Counselors — Social Workers|Section 337.015 - Practice of psychology regulated — practice of psychology, defined.

Effective - 28 Aug 1989   337.015. Practice of psychology regulated — practice of psychology, defined. — 1. No person shall represent himself as a psychologist in the state of Missouri unless he is validly licensed and registered under the provisions of this chapter. No person shall engage in the practice of psychology in the state of Missouri unless he is validly licensed and registered under the provisions of this chapter unless otherwise exempt under the provisions of sections 337.010 to 337.090.  2. A person represents himself as a "psychologist" within the meaning of this chapter when he holds himself out to the public by any title or description of services incorporating the words "psychology", "psychological", or "psychologist", or any term of like import, "psychometry", "psychometrics", "psychometrist", "psychotherapy", "psychotherapists", "psychoanalysis", "psychoanalyst", or variants thereof or when the person purports to be trained, experienced or an expert in the field of psychology, and offers to render or renders services as defined below to individuals, groups, organizations, or the public for a fee, monetary or otherwise; provided, however, that professional counselors licensed to practice under this chapter, or a physician licensed to practice pursuant to chapter 334, who specializes in psychiatry, may use any of such terms except "psychology", "psychological", or "psychologist" so long as such is consistent with their respective licensing laws.  3. The "practice of psychology" within the meaning of this chapter is defined as the observation, description, evaluation, interpretation, treatment, and modification of human behavior by the application of psychological principles, methods, and procedures, for the purpose of preventing, treating, or eliminating symptomatic, maladaptive, or undesired behavior and of enhancing interpersonal relationships, work and life adjustment, personal effectiveness, behavioral health, and mental health. The practice of psychology includes, but is not limited to, psychometric or psychological testing and the evaluation or assessment of personal characteristics, such as intelligence, personality, abilities, interests, aptitudes, and neuropsychological functioning; counseling, psychoanalysis, psychotherapy, hypnosis, biofeedback, and behavior analysis and therapy; diagnosis and treatment of mental and emotional disorder or disability in both inpatient and outpatient settings, alcoholism and substance abuse, disorders of habit or conduct, as well as the psychological aspects of physical illness, accident, injury, or disability; psychoeducational evaluation, therapy, remediation, and consultation; and teaching and training of psychological competence. Psychological services may be rendered to individuals, families, groups, and the public. The practice of psychology shall be construed within the meaning of this definition without regard to whether payment is received for services rendered.  4. The application of these principles and methods includes, but is not restricted to: diagnosis, prevention, treatment, and amelioration of adjustment problems and emotional and mental disturbances of individuals and groups; hypnosis; counseling; educational and vocational counseling; personnel selection and management; the evaluation and planning for effective work and learning situations; advertising and market research; and the resolution of interpersonal and social conflicts. ­­-------- (L. 1977 H.B. 255 § 2, A.L. 1981 S.B. 16, A.L. 1989 H.B. 738 & 720)