RISK FACTORS - GENETIC VUNERABILITY

Overview

genetic vulnerability = the idea that someone may be more likely to become an addict because of their genetic make up

this does not mean that they will definitely develop an addiction but they are more likely to, given the right circumstances

some individuals may be born with a genetic vulnerability or a genetic predisposition to develop an addiction

circumstances = exposure to a substance or the opportunity within their environment to take it

a gene environment interaction is necessary to bring about the addictive behaviour

slutske 2010

both male and female MZ twins were found to have much higher concordance rates compared to DZ twin pairs

Male twin pairs: 49% MZ vs 21% DZ

studied 2889 pairs of twins to investigate the role of genetic and environmental factors in the development of gambling addiction

Female twin pairs: 55% vs 21% DZ

this suggests there is a genetic component to gambling that can be present in both men and women

environmental factors are also likely to be involved, especially as concordance rates amongst MZ twins were not 100%

A1 variant of the DRD2 gene

research suggests that there is a specific gene involved in addiction

Blum et al. 1990

occurred with a much higher frequency in the DNA of samples taken from alcoholics compared to non alcoholics

reported that a particular variant (A1) of the dopamine receptor (DRD2) gene is associated with fewer dopamine receptor sites

individuals with this gene may not receive enough simulation from everyday activities. individuals continue to engage in addictive in behaviours

to compensate for the dopamine deficiency

weakness

suggesting that genes only predispose an individual to addiction as opposed to being the sole determining factor

no concordance rates in twin studies (MZ twins) have ever shown 100% concordance

diathesis stress model

an individual will not become addicted if they are not exposed to the substance in the environment

we inherit a genetic vulnerability for developing an addiction. however a disorder will only manifest itself if triggered by a life event

suggests that a gene environment interaction is needed for an addictive behaviour to develop