Page:The Modern Treatment of Mental and Nervous Disorders.djvu/13

— 11 — causes whose removal will lead to the disappearance of the symptom. The symptom may be regarded as the final result of a chain of causes, and treatment must be directed to the removal of those links which are the most important, and upon which the chain is mainly dependent.

The decision at issue, therefore, the question whether the chain of causes responsible for mental and nervous disorders is made up of entirely physiological or physical links, as the physiological conceptions of the nineteenth century would have us believe, or made up of mental links, as the newer psychological conception maintains, is one fraught with consequences of the utmost practical importance. The answer which seems to fit best the facts known to modern science is that neither of these one-sided conceptions is wholly correct, but that the causal chain contains both mental and physical factors in every case, although the relative importance of these factors differs greatly in the different types of disorder. We find a chain comprising such factors as constitutional peculiarities, including the