risk factors: genetics Flashcards
AO1: genetics
Definition
Overview
Slutske research
Dopamine receptor genes
Genetic vulnerability overview
Some people are born w a genetic vulnerability to substance abuse and other forms of ‘unhealthy behaviour’
Genetic definition
refers to the inherited characteristics that are passed from parents to children in the form of information carried on their chromosomes
Slutske study
Aus study of 2889 pairs of twins to investigate role of genetic and environmental factors in the development of gambling addiction.
Male MZ twins had a heritability estimate of 49% compared to 21% for DZ twins
The dopamine receptor genes
Blum and Payne:
Suggested that individuals who are vulnerable to drug addiction suffer from abnomally low levels of the neurotransmitter dopamine and a decreased ability to activate dop receptors in reward centre
This means anything that incr dop means euphoria
This is consistent w research involving the genetic origins of addictive behaviours
For example, Blum et al. reported that a particular variant of the dopamine receptor gene associated with decreased dopamine receptor availability (the A1 variant) occurred with a much higher frequency in the DNA of samples taken from alcoholics compared to non-alcoholics.
AO3:
lim: gender diffs
str: diathesis stress model
lim: gender diffs
Cannot account for gender differences.
Eg: although studies of male alcoholics have consistently supported
the important role played by genetic factors in the development of alcoholism, research with women has produced inconsistent findings (McGue, 1997).
McGue points out that only 2 out of 4 adoption studies have reported a
significant correlation between alcoholism in female adoptees and their biological parents. Likewise, only 2 out of 5 twin studies found significantly
greater concordance for alcoholism among female MZ twins than among
female DZ twins.
This suggests that genetic vulnerability may be less important in the development of alcoholism in women than in men.
Beta bias
str: Diathesis stress model
It can explain why some people develop addictions yet others who have the same environmental experiences and life pressures do not.
Some people are more likely to develop an addiction due to their genetic vulnerability. For example, the A1 variant of the dopamine-receptor gene has been found to be associated with cocaine dependence (Noble et al) and nicotine dependence (Connor et al).
This suggests that individuals who inherit this gene variant are more vulnerable to developing addictive behaviour because of their low levels of
dopamine and the increase in dopamine that is possible with drugs that activate the brain-reward pathway, giving the explanation external validity.
