The comparative pharmacology of some psychotropic drugs.

Interest in the mode of action of the psychotropic drugs has been growing rapidly during the last few years and at the same time the number of compounds known to be capable of affecting the higher centres of the central nervous system has greatly increased. The diversity of psychic and somatic effects produced by these drugs, the fact that they may have similar effects on some functions but opposite effects on others, and the lack of a precise and universally accepted terminology to describe these properties have led to much confusion and thwarted attempts to arrive at a satisfactory classification. As a contribution to a clearer understanding of the relationships between the psychotropic drugs the author of this review has undertaken a systematic examination of the effects of a number of the better known compounds on the various levels of the central nervous system. The antagonistic and synergistic effects of giving the drugs in combination are also discussed, as well as the possible relationships between the central effects and certain "basic" effects on somatic functions. Although the picture revealed is a very complex one and there are still many gaps, it is possible to recognize a number of characteristic types of psychotropic drug on the basis of which a system of classification may be developed.