Cognitive Theory of depression was developed by:

Cognitive therapy refers to a psychotherapeutic approach developed by Dr Aaron Beck. Cognitive therapy is one of the therapeutic approaches within the larger group of cognitive behavioural therapies. Cognitive therapy seeks to help the client overcome difficulties by identifying and changing dysfunctional thinking, behaviour and emotional responses. This involves helping clients develop skills for modifying beliefs, identifying distoed thinking, relative to others in different ways and changing behaviors'. Treatment is based on collaboration between client and therapist and on testing beliefs. Therapy may consist of testing the assumptions which one makes and identifying how some of one's usually unquestioned thoughts are distoed, unrealistic and unhelpful. Once, those thoughts have been challenged, ones feelings about the subject matter of those thoughts are more easily subject to change.