Psychotherapy treatment of mental and emotional disorders using psychological methods. Psychotherapy, thus, does not include physiological interventions, such as drug therapy , although it may be used in combination with such methods. This type of treatment has been used in one form or another through the ages in many societies, but it was not until the late 19th cent. that it received scientific impetus, primarily under the leadership of Sigmund freud. Although Freud’s theoretical formulations have come sharply into question, his treatment method involving individualized client-psychologist sessions has been used in modified forms for years. Behavior therapy aims to help the patient eliminate undesirable habits or irrational fears through conditioning. Techniques include systematic desensitization, particularly for the treatment of clients with irrational anxieties or fears, and aversive conditioning, which uses negative stimuli to end bad habits. Humanistic therapy tends to be more optimistic, basing its treatment on the theory that individuals have a natural inclination to strive toward self-fulfillment. Such methods include Albert Ellis’s rational-emotive therapy, where the therapist argues with the client about his negative ideas; and Aaron Beck’s cognitive restructuring therapy, in which the therapist works with the client to set attainable goals. Other forms of therapy stress helping patients to examine their own ideas about themselves.