The Malady, 'Depression', is not without significant individual and social burden, it is not surprising our calculated efforts are directed to it's origin, course, and treatment. This thesis, explores the significance of dysfunctional attitudes in the origin, course and evaluation of depression. Special attention is paid to the Cognitive Model Of Depression. It's content includes, the role in diagnosis, theoretical explanations and last but not least, the effect in therapy: Cognitive Behavioural Therapy.