W3 T1; Vulnerability, genes and environment
Gene importance in addiction
Point of research is to understand the differences between ppl influenced by
genetics and environment
E.g. smokers differ in amount of cigarettes smoked per day; some of this is
influenced by environment such as time and money
However, in controlled environments still variation seen showing genetic influence
The simple theory is that phenotype = genes + environment
Aim of studies is to identify genes contributing to variation; controlled experiments
are unethical so twin studies used
Genes account for 50-70% of variation in addiction-related phenotypes (heritability)
Environmental factors could appear as nuisance or error, but this is not always the
best approach
More complex theory includes interactions and correlations between e and g factors
Environment in addiction can have big effect on genetics
E.g. having strong genetic predisposition to alcohol but living in a country where it is
banned
Gene-environment relationships
Interactions: environment can directly interact with genetics
E.g. individuals with DDR2 long variant show much higher level of craving when
exposed to lit cigarette than those with DDR2 short variant
G-e correlations: genetic predisposition can affect likelihood of being exposed to
certain environmental factors
E.g. predisposition towards novelty seeking may be more likely to try new drugs
We need to understand both genetic and environmental factors to properly
understand addiction phenotypes
Gene-environment relationships in real world
Some states have more restrictive smoking policies (and potentially more negative
attitudes to it), which show lower heritability of adolescent daily smoking
Gene importance in addiction
Point of research is to understand the differences between ppl influenced by
genetics and environment
E.g. smokers differ in amount of cigarettes smoked per day; some of this is
influenced by environment such as time and money
However, in controlled environments still variation seen showing genetic influence
The simple theory is that phenotype = genes + environment
Aim of studies is to identify genes contributing to variation; controlled experiments
are unethical so twin studies used
Genes account for 50-70% of variation in addiction-related phenotypes (heritability)
Environmental factors could appear as nuisance or error, but this is not always the
best approach
More complex theory includes interactions and correlations between e and g factors
Environment in addiction can have big effect on genetics
E.g. having strong genetic predisposition to alcohol but living in a country where it is
banned
Gene-environment relationships
Interactions: environment can directly interact with genetics
E.g. individuals with DDR2 long variant show much higher level of craving when
exposed to lit cigarette than those with DDR2 short variant
G-e correlations: genetic predisposition can affect likelihood of being exposed to
certain environmental factors
E.g. predisposition towards novelty seeking may be more likely to try new drugs
We need to understand both genetic and environmental factors to properly
understand addiction phenotypes
Gene-environment relationships in real world
Some states have more restrictive smoking policies (and potentially more negative
attitudes to it), which show lower heritability of adolescent daily smoking
