THE PHARMACODYNAMIC EFFECTS OF ANTIDEPRESSANT DRUGS - A SHORT REVIEW

Resent research on the mechanisms of action of antidepressant treatmen t (ADT) has led to major revision of earlier concepts. The monoamine d eficiency hypothesis seems to be too simplistic, as it does not accoun t for the great temporal discrepancy between the rapid drug-induced bi ochemical effects of amine uptake and catabolism, which occurs within hours, and the antidepressant response, which occurs after at least 7- 14 days. The pharmacodynamic effects of ADT are obviously complex invo lving a great number of interacting transmitter and receptor systems i n the central nervous system. Secondary adaptive changes in neuronal s ystems seem to play an integral and possibly pivotal role in antidepre ssant drug action. Our knowledge about the details is sparse, primaril y because most investigations on the subject are based on animal studi es or in vitro technics, whereas the number of clinical investigations of the antidepressant drug effect on the living human organism is lim ited. This fact may explain the often-found discrepancy between experi mental and clinical effect.