A psychologist is a person who studies human behavior, emotion, and mental states. While anyone with a doctoral degree in psychology or a related field may be referred to as a psychologist, the term is commonly associated with psychologists who provide therapy and clinical assessments.

Training and Licensure

Psychologists are generally members of the American Psychological Association. To practice as a psychologist or to market themselves using the term, psychologists must obtain a state license. Licensing requirements vary slightly in each state, but may require a licensing examination, annual or biennial continuing education classes, and a certain number of supervised clinical hours.

Roles of Psychologists

Psychologists fill a wide variety of psychological roles. These include:

  • Clinical psychologist – Specialists who may provide individual, group, or couples therapy.
  • Forensic psychologist – Psychologists involved with the judicial system who may fill a number of functions including treating incarcerated persons, performing court-ordered evaluations, and assessing the competence of criminal defendants to stand trial.
  • Comparative psychologists – Comparative psychologists study the behavior of non-human animals, and may apply their research to human behavior.
  • School psychologist – These psychologists provide psychological services such as assessment, counseling, and academic testing in a school setting.

Psychologist vs. Psychiatrist

Psychologists are easily confused with psychiatrists because both specialists have doctoral degrees. However, unlike psychiatrists, psychologists do not have medical degrees and therefore cannot prescribe medication. However, some advocacy groups have lobbied state legislatures for prescribing rights, arguing that psychologists are qualified to assess and diagnose mental illnesses and that giving them the right to prescribe medication can benefit clients and reduce healthcare costs. In Louisiana, psychologists who have master’s degrees in psychopharmacology in addition to their doctoral degree may prescribe medication under the supervision of and in consultation with the patient’s medical doctor. Psychologists in Louisiana who can prescribe medications are referred to as medical psychologists.


  1. Colman, A. M. (2006). Oxford dictionary of psychology. New York, NY: Oxford University Press.
  2. Medical psychologist may prescribe medication. (n.d.). Louisiana Psychological Association. Retrieved from


Last Updated: 04-18-2016

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