Psychotherapy is a general term referring to therapeutic interaction or treatment contracted between a trained professional and a client or patient; family, couple or group. The problems addressed are psychological in nature and of no specific kind or degree, but rather depend on the specialty of the practitioner.
Psychotherapy aims to increase the individual's sense of his/her own well-being. Psychotherapists employ a range of techniques based on experiential relationship building, dialog, communication and behavior change that are designed to improve the mental health of a client or patient, or to improve group relationships (such as in a family).
Cognitive Analytic Therapy (CAT) is a form of psychotherapy which is distinctive due to its intensive use of reformulation, its integration of cognitive and analytic practice and its collaborative nature, involving the patient very actively in their treatment.