Sandler discusses, not theories of specific causes of psychosomatic illness, but rather the theoretical mechanisms that bridge the gap between psychic conflict and somatic illness. He discusses the mechanisms involved in hysterical conversion, the organ neuroses, and the pathological processes resulting from fantasied stress. The physiological imbalance of the body (due to psychological causes) may possibly give rise, reactively, to certain benign or malignant tumors.

Sandler reminds us that the emergence of a symptom can create false psychopathology quite different from that which started the initial functional disturbances finally leading to the symptom. The manifest psychopathology, therefore, is not always the true one. A reorganization of the whole personality takes place once a symptom is conscious. From the economic point of view the final outcome may be considerably different from the state of affairs existing at the time of the beginning of the pathological process,—a process which later produces symptoms.