Based on psychological testing and psychotherapeutic experience, the author discusses four aspects of obsessive compulsive functioning in detail: rigidity, compulsive activity, the sense of 'should', and the loss of reality. This last refers to the way in which the compulsive often behaves as though he is deluded. Actually the ego is constricted; its attention is focused on peripheral 'technical' details of experience and a loss of the feeling of conviction.