A contemporary hypothesis is that epigenetic mechanisms contribute to the formation and
persistence of fear memories and that epigenetically based pharmacotherapy may provide a new
avenue of drug treatment for PTSD-related cognitive symptoms (110). Potential domains in which
to develop new epigenetic pharmacological agents that will allow novel treatments of PTSD-
associated cognitive dysfunction include facilitated therapeutic relearning and enhanced extinction
of conditioned and contextual fear. Thus, clinical stress disorders such as PTSD might be the
first area wherein epigenetic pharmacology generally and DNA methylation specifically might
be targeted for therapeutic effect. Indeed, numerous recent studies have indicated that HDAC
inhibitors are beneficial for ameliorating specific conditioned fear responses in animal models.