Mental phenomena, like physical ones, arise not spontaneously or at random, but from adequate causes in accordance with natural law; i.e., here, as elsewhere, applies the doctrine of determinism.

Mental disorders present to the student two aspects: form and content. The chapters in this Manual dealing with symptomatology are devoted to a consideration of forms of disorder. For an understanding of the particular factors at work in a given case and for the more purposeful planning of psychotherapy a study of content must also be made.

Such a study must concern itself not merely with the patient's unguided formulations, but with a systematic probing for psychic factors many of which have passed beyond his present recollection or awareness. This is the particular task of psychoanalysis.

The Realm Of The Unconscious

One's field of consciousness is at all times limited; in other words, the number of representations within the scope of actual awareness at any given moment is small in comparison with one's total mental content. The readiness with which stored impressions can be recalled varies. There are probably many factors on which this variation depends, but one of these is of special interest for psychoanalysis - the factor of repression.

1 A. A. Brill. Psychanalysis: Its Theories and Practical Application. - C. G. Jung. The Theory of Psychoanalysis. - E. Jones. Papers on Psychoanalysis. - O. Pfister. The Psychoanalytic Method. English translation by C. R. Payne. - S. E. Jelliffe. The Technique of Psychoanalysis.

Ideas are charged with affect. In cases in which this affect is of a painful kind the ideas may be repressed, i.e., relegated to the realm of the unconscious by a protective mechanism.

That which is in the unconscious is not without influence on behavior. The latter is, indeed, for the most part motivated by unconscious factors. Notably repressed ideas, wishes, or "complexes" influence behavior, and sometimes in such a way as to produce pathological manifestations, either by transference of affect energy from the painful idea to one assimilable in consciousness (phobias, obsessions), or by conversion into a somatic manifestation (tremor, aphonia, paralysis).

Many repressed ideas or complexes are of a sexual nature. Mental disorders are very often manifested or produced by sexual maladjustment, and it is therefore incumbent on the student of psychiatry to make careful study of the subject of sexuality.