The Interrelations of Mental Defect and Mental Disorder

The development of the concepts underlying the terms mental deficiency and psychosis with mental deficiency, may be arbitrarily divided into four periods, which to a considerable degree, overlap. The first period is concerned with the separation of the two principal groups, mental deficiency and mental disorder. Even before the time of Hippocrates some differentiation had been made between the idiot, who was feeble-minded from birth and the dement, who had deteriorated from a previously normal status. Pinel (1), however, as late as 1806 used the term idiocy loosely, and included many cases of terminal dementia and other deteriorated states. The end of the first period is marked by the definitive separation by Esquirol (2), in 1828, of mental defect and mental disorder, but it was not till 1886, in England, that a legal differentiation was made been insanity and feeble-mindedness.