Addiction - GENETIC risk factors Flashcards
(11 cards)
Outline genes as a risk factor for addiction
We have a genetic predisposition or vulnerability to addiction. Addiction only develops if a person is exposed to a substance—genes increase risk, but do not guarantee addiction.
Why don’t genes alone determine whether someone becomes addicted?
Genes are not inevitable causes. A person must first be exposed to a drug, and whether this happens depends mainly on psychosocial factors such as peer pressure, stress, or environment.
According to Blum (1991), what role does dopamine play in genetic vulnerability to addiction?According to Blum (1991), what role does dopamine play in genetic vulnerability to addiction?
Blum proposed that people vulnerable to addiction have low dopamine levels and fewer dopamine receptors (especially D2 receptors) in the brain’s reward system, making them more likely to seek out substances that increase dopamine.
What is the D2 receptor and how is it linked to addiction?
The D2 receptor is a type of dopamine receptor. A low number of D2 receptors is linked to increased risk of addiction. The number of these receptors is genetically determined.
What did Pianezza et al. (1998) find about the CYP2A6 enzyme and nicotine addiction?
They found that individuals lacking a fully functioning CYP2A6 enzyme metabolise nicotine more slowly and therefore smoke less. Those with the full version of the enzyme are more at risk of nicotine addiction due to faster metabolism.
What does the CYP2A6 enzyme do and how does it relate to genetic vulnerability?
CYP2A6 is responsible for metabolising nicotine. Its expression is genetically determined, meaning some people are more vulnerable to nicotine addiction based on how efficiently they process the drug.
What does the diathesis-stress model say about addiction and genetic vulnerability?
It suggests that addiction arises from an interaction between genetic vulnerability (diathesis) and environmental stressors. Not everyone exposed to stress becomes addicted—only those with the underlying vulnerability are at higher risk.
How does the dopamine receptor gene variant (A1) relate to addiction risk?
The A1 variant of the dopamine receptor gene is linked to lower dopamine function. People with this gene are more likely to become dependent on substances like nicotine and cocaine that activate the brain’s reward system.
What is a strength of genetic explanations for addiction?
They help explain individual differences in addiction risk, even when people share similar environments. Genetics account for why some develop addictive behaviour while others don’t.
What is a limitation of genetic explanations for addiction?
McGue (1997) found stronger genetic links in male alcoholics, but inconsistent results in females. Only 2 out of 5 twin studies found higher concordance in female MZ than DZ twins, suggesting weaker genetic influence in women. This isn’t explained by the genetic risk factor explanation
Outline Kendler et al’s study supporting evidence for genes as a risk factor. How does it support this factor?
used data from the National Swedish Adoption Study. They looked at adults who had been adopted away as children from biological families in which at least one parent had an addiction. These people had a significantly greater risk of developing an addiction themselves (8.6%) compared with adopted away individuals with no addicted parent in their biological family (4.2%). This suggests that the greater the genetic vulnerability the children had, the higher the likelihood of developing an addiction.
