Addiction Genes
Genetic Factors
- People who are more closely related should share similar behaviour
Goldmann et al (2005)
- Addictions are “moderately to highly heritable”
- Heritability of addictions ranges from +39 for hallucinogens, +72 for cocaine
Inheritance Studies
Prescott and Kendler (1999)
- Personal interviews to assess alcohol abuse
- 3516 twins in Virginia between 1940 - 1974
- Concordance was higher between MZ twins
Kendler et al (2012)
- Large scale adoption study in Sweden
- Biological parents with a drug addiction cause a higher risk of having a drug addiction
Agrawal and Lynskey (2008)
- Genetic influence of addiction ranges 30 - 70%
- Highlighted importance of interplay between genes and environment
Associated Genes
- DRD2 and ADH
DRD2 - dopamine D2 receptor
- People have fewer dopamine receptors in area that provides sense of pleasure
ADH - alcohol metabolised
- There are some variants that decrease risk of alcoholism (leads to unpleasant reactions)
- Variations can break it down much slower
Diathesis - Stress Model
- A disorder only develops when a genetic predisposition to a particular disorder is
triggered by an environmental stressor
Evaluation
- Reductionist approach
- Lack of determinism
- Rules out environmental factors
- Culture / gender bias
+ Supporting evidence from twin and family studies
+ Supported by gene research
+ Can lead to personalised medicine
Genetic Factors
- People who are more closely related should share similar behaviour
Goldmann et al (2005)
- Addictions are “moderately to highly heritable”
- Heritability of addictions ranges from +39 for hallucinogens, +72 for cocaine
Inheritance Studies
Prescott and Kendler (1999)
- Personal interviews to assess alcohol abuse
- 3516 twins in Virginia between 1940 - 1974
- Concordance was higher between MZ twins
Kendler et al (2012)
- Large scale adoption study in Sweden
- Biological parents with a drug addiction cause a higher risk of having a drug addiction
Agrawal and Lynskey (2008)
- Genetic influence of addiction ranges 30 - 70%
- Highlighted importance of interplay between genes and environment
Associated Genes
- DRD2 and ADH
DRD2 - dopamine D2 receptor
- People have fewer dopamine receptors in area that provides sense of pleasure
ADH - alcohol metabolised
- There are some variants that decrease risk of alcoholism (leads to unpleasant reactions)
- Variations can break it down much slower
Diathesis - Stress Model
- A disorder only develops when a genetic predisposition to a particular disorder is
triggered by an environmental stressor
Evaluation
- Reductionist approach
- Lack of determinism
- Rules out environmental factors
- Culture / gender bias
+ Supporting evidence from twin and family studies
+ Supported by gene research
+ Can lead to personalised medicine
