We have determined what we mean by cerebral control, how it can be defective, and the results produced by insufficient control. We will now apply this information to the treatment of psychoneurosis. If we are reserving our application to include only this class of illness, it is because the various forms of psychoneurosis seem to exemplify what happens when there is insufficient cerebral control, since these cases respond better than any other form of illness to the process
We can, in effect, assume that in psychasthenic patients the conscious and subconscious parts of the brain are normal and have not undergone any organic alterations, conditions which are indispensable for complete re-education. In all purely mental illnesses, there is more than an absence or insufficiency of control - there is always some alteration of the conscious mind. In cases of hysteria, for example, which is certainly characterized by obvious modifications of this kind, we would not know how to tell whether or not the disorder was uniquely a problem of mental control.
Its nature is so complex that it would be difficult to accept the instability of mental equilibrium as its absolute cause. In psychasthenic cases, on the other hand, even the most inexperienced observer can recognize in each symptom and each step in its development, an obvious insufficiency, so that it would be hard to refute the fact that “all cases of psychasthenia are caused by a lack or an insufficiency of mental control.”
This conclusion may seem somewhat hastily drawn, but we will attempt to prove it by analyzing the psychological symptoms found in all cases of psychoneurosis.