The Cognitive Behavioral Analysis System of Psychotherapy (CBASP) by James McCullough is the first psychotherapeutical approach specifically designed for chronic depression. Whereas its efficacy has recently been studied, empirical investigations on the underlying etiopathological hypotheses are missing. McCullough postulates that chronically depressed patients - particularly those with early onset - think preoperationally. This term was coined by J. Piaget and includes egocentrism in the views of self and others and incapacity for authentic interpersonal empathy. In accordance, empirical studies indicate a deficit in theory of mind (ToM) in depressed individuals.
