How do genetics (genetic predisposition) and the environment work together to cause substance abuse in individuals? What is the likely role of epigenetics in this process?

. Vulnerability to

develop an addiction to drugs is dependent on genetic, environmental, social and

biological factors. In particular, the interactions of environmental and genetic factors

indicate the significance of epigenetic mechanisms, which have been found to occur in

response to illicit drug use or as underlying factors in chronic substance abuse and

relapse. Epigenetics is defined as the heritable and possibly reversible modifications in

gene expression that do not involve alterations in the DNA sequence. This review

discusses the various types of epigenetic modifications and their relevance to drug

addiction to elucidate whether epigenetics is a predisposing factor, or a response to,

developing an addiction to drugs of abuse.