[Correlation between plasma concentration and clinical effect of neuroleptics and antidepressants]

Results of investigations concerning the correlation between plasma concentrations and clinical effect of neuroleptics and antidepressives are summarised. In the case of neuroleptics there is in general no relationship between clinical parameters of activity and plasma concentration. For antidepressives there is, in most cases, a correlation between side-effects and plasma concentrations. Whether the therapeutic effect is dependent on the plasma concentration or not, is however open to some doubt. The practical value of plasma concentration estimations during therapy with the above mentioned drugs is therefore limited. Inadequate efficacy and/or poor tolerance can occasionally be explained by estimating plasma concentrations which alone, however, scarcely allow one to make prophecies. In determination of the optimal individual dosage must continue to be an empirical process based on clinical observations and experience.