Pharmacogenetic study with diazepam in twins.

In a study with healthy volunteers (6 monozygotic and 4 dizygotic twin pairs) we followed up diazepam serum levels and psychotropic effects of diazepam after single-dose administration. We found that pharmacokinetic properties of diazepam as well as its influence on memory and performance are probably not under genetic control. On the other hand, genetic factors seem to contribute to effects of diazepam on affectivity.