Bio exp - genetics

• Goldman et al stated that addictions are moderately to highly heritable
• two genes that have been identified to have an influence in addiction is the ADH gene and the DRD2 gene.
• A1 variant of the DRD2 gene 


  Those who have this variant fewer dopamine receptors in an area of the brain that provides us with a sense of pleasure in respomse to normally addictive behaviour
• Those with the A1 variant may engage in addictive behaviour because lower dopamine receptors means that they try top compensate for this by overstimulation by engaging in these behaviours.
• Comings et al

  Found that 44% of smokers and ex smokers carry the A1 gene variant compared to 26% of the population. Similar results are also found in gambling addicts as 51% of them carry the A1 variant compared to 26% of non addicts
• ADH Gene 


  it is responsible for how alcohol metabolises within the body.
• Certain variants of the ADH gene have been found to have an effect on the way alcohol is metabolised, and slows down the metabolism of alcohol making the individual less affected by alcohol potentially making them feel the need to drink more in order to feel the effects of alcohol quicker and harder almost.
• the ADH gene has also been linked to decreasing the risk of alcoholism, as a variant can lead to an increase in the production of the enzyme that that breaks down alcohol, making them experience unpleasant side effects like nausea and facial flushes.
• the ADH gene linked to the lower rates of alcoholism is supported by alcohol rates in east Asia. as many people in east Asia have this gene, meaning that many get an unpleasant reaction to alcohol, causing low rates of alcoholism .