Clinical psychology is the application of psychology to mental illness or mental health problems. The term was introduced in a 1907 paper by the American psychologist Lightner Witmer (1867-1956).

Clinical psychologists are involved in the diagnosis, assessment, and treatment of patients with psychiatric disorders, as well as research about all of these areas of clinical practice. Their clinical work may include the use of 'talk therapies' (i.e.,psychotherapy such as cognitive therapy and psychoanalysis), or the use of psychological tests to assess certain aspects of psychological functioning.

Some clinical psychologists may specialize in understanding, assessing, and treating brain injury and neurocognitive deficits to become clinical neuropsycholgists.

Prior to the 20th century, there was little, if any, clinical help available for sufferers of mental health problems. In the early 20th century, Sigmund Freud developed a therapy known as psychoanalysis. The practice of psychoanalysis was initially restricted to psychiatrists (medical doctors who specialise in treating mental illness) but is currently practiced by psychologists and other mental health practitioners. Psychoanalytic training is a lengthy endeavour, often taking the analytic candidate, who is already a psychologist or psychiatrist, an additional five to ten years to complete.

Clinical psychology developed partly as a result of a need for additional clinicians to treat mental health problems, and partly as psychological science advanced to the stage where the fruits of psychological research could be successfully applied in clinical settings.

See also

• clinical neuropsychology
• mental illness
• psychotherapy
• psychological testing
• Important publications in clinical psychology