Can You Be Predisposed To Addiction?
According to recent statistics, 2.4% of adults identify themselves as frequent drug users while it’s estimated that approximately 602,391 people in the UK are dependent drinkers with alcohol misuse being the fifth biggest risk factor for death and health-related problems. Since addiction has been recognised as a serious disease, researchers have been hoping to find a gene that could explain why some people are more prone to addiction than others.
Can You Be Genetically Predisposed to Addiction?
Addiction is a complex disease that is influenced by environmental factors. For example, young people are more likely to try smoking or drinking if their peers do the same or if their parents are frequent users.
Even though it’s difficult to identify genes directly responsible for drug response, previous studies looked at genes that might alter resiliency, affect reward systems and treatment response. For example, one of the older research found that low levels of a protein called PSD-95 might be linked to memory problems and can predispose someone to become addicted, as mice with that characteristic took longer to get out of the maze and were more vulnerable to cocaine addiction. 
Most recently, Korea Brain Research Institute proposed that overexpression of dopamine D2 receptors (DRD2s) might play an important factor in cocaine addiction. Drugs cause an increase in dopamine that is a part of the brain’s reward system. When dopamine receptors become activated, we feel good and crave more, which is how addiction happens. The more we expose ourselves to dopamine, the more dopamine receptors we make which means we need even more dopamine to fill them. 
As dopamine plays a key role in all types of addictions, this discovery is a huge step towards understanding the exact neurobiological mechanisms that can cause it.
Statistics: https://alcoholchange.org.uk/alcohol-facts/fact-sheets/alcohol-statistics , https://www.rehab4addiction.co.uk/trends/drug-addiction-statistics-uk