I THE development of a systematic psychological approach to psychotic conditions began with the twentieth century. Before this new era dawned, the position of psychiatry as a branch of medicine rested on somewhat frail grounds. It was even contended by Kant, in response to the legitimist claims of Hufeland, the eminent German alienist, that the consideration and treatment of mental disease belonged, not to the physician, but to the philosopher. Considering how long it has taken medical science to recognize the psychological criterion in the study of mental disorders, it is more than possible that Kant was justified. It must also be confessed that psychology was almost as powerless as medicine to deal with the problems and disorders of the mind until Freud and J ung began to make use of the purposive or teleological conception of unconscious mental processes.