Abstract
The individual response to psychotropic drugs, although dose-dependent, is not stable. In some countries the variations in drug response are more pronounced, indicating a higher level of susceptibility of patients. Factors of importance influencing the response to psychotropic drugs may be subdivided into genetic and environmental ones. In research meant to clarify the difference in relation to the geographic, ethnic and sociocultural differences among nations and individuals of various ethnic origins in their alien communities, consideration must be given to genetic factors and environmental differences in the daily surroundings. The importance of both social and psychological factors should be recognized in the evaluation of effectiveness of pharmacotherapy.