Psychoanalysis was perhaps the first specific school of psychotherapy, developed by Sigmund Freud and others through the early 20th century. Trained as a neurologist, Freud began focusing on problems that appeared to have no discernible organic basis, and theorized that they had psychological causes originating in childhood experiences and the unconscious mind. Techniques such as dream interpretation, free association, transference and analysis of the id, ego and superego were developed.
Behaviorism developed in the 1920s, and behavior modification as a therapy became popularized in the 1950s and 1960s. Notable contributors were Joseph Wolpe in South Africa, M.B. Shipiro and Hans Eysenck in Britain, and John B. Watson and B.F. Skinner in the United States. Behavioral therapy approaches relied on principles of operant conditioning, classical conditioning and social learning theory to bring about therapeutic change in observable symptoms. The approach became commonly used for phobias, as well as other disorders.
During the 1950s, Albert Ellis originated Rational Emotive Behavior Therapy (REBT). A few years later, psychiatrist Aaron T. Beck developed a form of psychotherapy known as cognitive therapy. Both of these generally included relatively short, structured and present-focused therapy aimed at identifying and changing a person's beliefs, appraisals and reaction-patterns, by contrast with the more long-lasting insight-based approach of psychodynamic or humanistic therapies. Cognitive and behavioral therapy approaches were combined and grouped under the heading and umbrella-term Cognitive behavioral therapy (CBT) in the 1970s. Many approaches within CBT are oriented towards active/directive collaborative empiricism and mapping, assessing and modifying clients core beliefs and dysfunctional schemas. These approaches gained widespread acceptance as a primary treatment for numerous disorders. A "third wave" of cognitive and behavioral therapies developed, including Acceptance and Commitment Therapy and Dialectical behavior therapy, which expanded the concepts to other disorders and/or added novel components and mindfulness exercises. Counseling methods developed, including solution-focused therapy and systemic. During the 1960s and 1970s Eugene Heimler, after training in the new discipline of psychiatric social work, developed Heimler method of Human Social Functioning, a methodology based on the principle that frustration is the potential to human flourishing.
ERP developed out of the Cognitive Behavior Therapy movement. It came about in the 1960s and 1970s as a result of research on OCD. ERP has become the most prominent psychological treatment for OCD today.