Biological Explanation 2: Addiction Genes Flashcards
What genes are associated with addiction?
DRD2, ADH & ALDH genes.
What characteristics do individuals have with the A1 variant of the DRD2 gene?
They have fewer dopamine receptors in an area of the brain that provides us with a sense of pleasure in response to certain behaviours such as eating.
For individuals with the A1 variant of the DRD2 gene, how can this lead to addiction?
With the lower number of dopamine receptors individuals may try and compensate for this by overstimulation through engaging in addictive behaviour.
David Comings Et Al. (1996)
Found that 48.7% of smokers and ex-smokers carried the A1 variant of the DRD2 gene compared with 25.9% of the general population.
What are ADH and ALDH genes responsible for?
The process of how alcohol is metabolised in the body.
Explain the process of metabolising alcohol
An enzyme called alcohol dehydrogenase (ADH) breaks down alcohol into acetaldehyde. Then another enzyme called acetaldehyde dehydrogenase (ALDH) breaks it down further into acetic acid and water.
Why have variants of ADH genes been linked to increased risk of alcoholism?
The individual might break down alcohol at a much slower rate than others, meaning they are more likely to drink more and potentially become addicted.
Higuchi et al. (2006)
Found lower activity variants of ADH genes have been associated with an increased risk of alcohol dependence in oriental populations.
What does the diathesis-stress model suggest?
Suggests that a disorder such as addiction only develops when a genetic predisposition to a particular disorder is triggered by an environmental stressor.
Kaufman et al., 2007
The serotonin transporter gene has been linked to the development of alcoholism, but not on its own. It appears to interact closely with environmental factors such as maltreatment in childhood.
