INTRODUCTION One of the problems in the present debate about neurochemical imbalances is that almost every word in the English language has at least two meanings, and sometimes four or five. Some English speakers deplore this state of affairs and regard it as an endless source of confusion. Others consider it an indication of the richness of the language and its ability to express finely tuned nuances. Others use it as a tool of obfuscation. In ordinary English, as spoken and written by ordinary people, the terms illness and disease are largely synonymous, and they mean: a maladaptive condition caused by a biological pathology.