As the derivation of the name indicates, psycho-neuroses are functional nervous affections dependent on states of mind. They are not necessarily originated by the mind, though they may be. Their spontaneous occurrence as pure psychic phenomena, however, is rather rare. There is practically always some slight physical cause. This may be severe, for all diseases have neurotic accompaniments that disturb the nerves involved and exaggerate the original symptoms. In most cases the patient has no serious interest to divert his or her mind from this occupation with self, and as a consequence the particular feeling fills up the whole of consciousness, and as it is painful to begin with, the pain, following Cajal's law of avalanche, may become almost intolerable.

It is of primary importance to remember, however, that there is practically always a physical basis for these curiously interesting affections which are so difficult to treat and which have so often proved the despair of physicians. While the attitude of mind must be changed, the physical state itself must be corrected. These two things must be secured at the same time, however, for attention to the physical state without correction of mental attitude will usually only emphasize the condition by calling further attention to the symptoms. This is especially true of local treatment. The mind must, above all, be treated and diversion of attention secured. Psycho-neuroses may occur in connection with sensory or motor nerves. The patient may either complain of intense pain in some part of the body for which there is but a very slight basis, or may be unable to move certain muscles, or there may be a combination of sensory and motor symptoms with complaint of pain on movement. The painful conditions are most important because they prove a source of worry and anxiety to the patient's friends, as well as often of such annoyance at unsuitable hours as deprives those near them of rest to a degree that may undermine health.{586}