The Genetics and Epigenetics of Addiction

Addiction is a topic that has become familiar to the citizens of the United States. But why do some become addicted to substances while others do not? Family studies that have been conducted suggest that as much as half of a person's risk of becoming addicted depend on their genetic makeup. Research on the human genome has shown that, on average, the DNA sequences of any two people are 99.9 percent the same. However, that 0.1 percent variation is profoundly important—it’s still 3 million. These differences contribute to visible variations, like height and hair color, and invisible traits, such as increased risk for or protection from certain diseases such as heart attack, stroke, diabetes, and addiction. By pinning down the biological basis of this risk scientists would be able to combat the problem of addiction. Epigenetics is the study of functional, and sometimes inherited, changes in the regulation of gene activity and expression that are not dependent on gene sequence (Chadwick 317-324).  These epigenetic marks can affect health and even the expression of the traits passed to children. For example, when a person uses cocaine, it can mark the DNA, increasing the production of proteins common in addiction. Increased levels of these altered proteins correspond with drug-seeking behaviors in animals. "Histones, as another example, are like protein spools that provide an organizational structure for genes. Genes coil around histones, tightening or loosening to control gene expression. Drug exposure can affect specific histones, modifying gene expression in localized brain regions. Science has shown that manipulation of histone-modifying enzymes and binding proteins may have promise in treating substance use disorders" (Heller, Cates, Pena 1720-1727). The division of Neuroscience and Behavior at the NIDA's genetics research program is currently researching the genetics and epigenetics controlling addiction which hopefully will provide better ways to combat it. 

 This article was incredibly interesting, being someone who studies science and has struggled with addiction in the past, I found the article and the research being done promising. Having a family history of addiction is common among addicts (including me) I meet and individuals I talk to, which has always lead me to believe there is a genetic link to addiction; hopefully this research sheds light on the causes of addiction and helps individuals not go through the things that addicts in the past have had to go through.

1. Heller EA, Cates HM, Peña CJ, et al. Locus-specific epigenetic remodeling controls addiction- and depression-related behaviors. Nat Neurosci. 2014;17(12):1720-1727.
2. Chadwick LH. The NIH Roadmap Epigenomics Program data resource. Epigenomics.2012;4(3):317-324

https://www.drugabuse.gov/publications/drugfacts/genetics-epigenetics-addiction
https://www.drugabuse.gov/about-nida/organization/divisions/division-basic-neuroscience-behavioral-research-dbnbr/genetics-molecular-neurobiology-research-branch-gmnrb