Epigenetic Effects of Currently Used Psychotropic Drugs

Epigenetic regulatory mechanisms are influenced by many pharmaceutical compounds including psychotropic drugs. In this chapter, the current state of knowledge on how several traditional psychotropic drugs alter the epigenome is reviewed. Sodium valproate is the most obvious example because of the fact that it is a known HDAC inhibitor. Antidepressants, including selective serotonin reuptake inhibitors (fluoxetine, citalopram), as well as tricyclic antidepressants (imipramine, amitriptiline) and monoamine oxidase inhibitors, influence the epigenome. Antipsychotics (clozapine, haloperidol) and to a lesser extent lithium influence the epigenome, and for these compounds there is evidence that part of the epigenetic effects are mediated via microRNAs. The effects of currently used psychotropic drugs on epigenetic mechanisms of gene expression and how these effects may contribute to the therapeutic benefits of these drugs are discussed. The role of epigenetics in psychopharmacological treatment response is just starting to become clear, but what we do know suggests that there is vast potential for further development of epigenetic drugs.