[What is next in the development of antidepressives?]

After some findings concerning the mode of action of antidepressants, it was possible to hypothesize the molecular basis of depressive disorders (monoamine hypothesis, receptor hypothesis). These informations made the preparation of drugs acting by a completely new mechanism. Possible an antidepressant effect was observed after the administration of GABA-ergic agonists, or agents influencing dopaminergic transmission, S-adenosylmethionine, and drugs influencing second messenger systems. As a consequence of these findings, the GABA-ergic hypothesis, hypothesis of endogenous ligand (barinine hypothesis is discussed in more detail), and second messenger hypothesis of affective disorders were formulated. Agents influencing second messenger systems and S-adenosylmethionine seem to be a promising field of future investigation.