Many psychiatrists regard mysticism as a form of mental disorder or as a danger for mental health. Two cases of so called `esoteric students', suffering from severe psychosis, are presented. It is argued that in the first case disruption was not caused by the practice of mysticism but that a line of rupture was already present. In the second case injudicious use of esoteric techniques is suggested to be the unbalancing factor. Serious esoteric schools are well aware of the problem of incompetent use of esotericism. A closer look at the essence of mysticism reveals that the gulf that separates it from modern psychology is not really insurmountable. To close the gap it is necessary to acquire first hand knowledge of mysticism, as is e.g. done by transpersonal psychologists. It is concluded that there is no danger in esoteric exercises, provided the student is mentally stable and has competent guidance. A psychiatrist should have some basic knowledge of mysticism, because patients will only confide him such problems if they feel that he has a genuine interest in it.