Compliance has been defined as "the degree of constancy and accuracy with which a patient follows a prescribed regimen, and engagement can be thought of as the "emotional involvement or commitment of a person. Compliance is related to algorithmic tasks with well-defined rules of conduct and with a priori acknowledged outcomes. They follow (a) a set of established instructions, (b) down a single pathway, (c) to one conclusion. Algorithmic tasks, which require compliance to be successful, are best suited to routine work. Engagement, on the other hand, is related to heuristic tasks, for which no algorithm exists, where one has to experiment with possibilities and devise new solutions. Therapy, and even more specifically, psychotherapy with addicted patients, has continuously to be developed between these two pole