A scientifically proven four-step self-treatment for obsessive-compulsive disorder (OCD) which enables people to modify their behaviour & their brain chemistry. OCD is a condition which affects millions of people worldwide. This work shows how sufferers can cure themselves by their own determination rather than through psycho-pharmaceuticals. Using real-life examples from real patients it scientifically validates this cognitive-behavioural self-treatment through visually striking brain imaging studies which show that people can systematically modify their own brain metabolic activity.