Using Epigenetic Tools to Investigate Antidepressant Response

Abstract Major depressive disorder is a chronic and debilitating illness. It is most commonly treated with antidepressant drugs, however, as the majority of patients do not respond on their first trial or following several adequate trials, there is great interest in identifying biological factors that may help select the most appropriate treatment for each patient and in understanding biological processes that mediate treatment response. Epigenetic factors, such as non-coding RNAs (ncRNAs), hold potential as biomarkers of antidepressant response. In this chapter, we review key methodological considerations when investigating ncRNA biomarkers, including biological samples and technologies which have been used in these studies. Secondly, we summarize findings from studies investigating ncRNAs in antidepressant treatment response. Finally, we discuss some of the future directions which will be necessary for the development of clinically relevant epigenetic tools.