ABSTRACT
IT is impossible to predict the psychological effects of a drug with any certainty from a knowledge of its chemical constitution alone, despite the increasing success with which new drugs, designed to meet the needs of psychiatric drug therapy, have been synthesized, especially in the past ten or fifteen years. A very slight variation in molecular structure may completely alter the action of a compound. For instance, two drugs which have identical composition and only a slight difference in structure are Frenquel, an ataractic drug which antagonizes stimulants, and Meratran, an isomer of Frenquel which is however a central stimulant.
