Biological Approach To Addiction
Discuss biological approaches to addiction (9+16 Marks)
The genetics of addiction: * People who have an addictive personality are likely to be predisposed to it because of their genes. * Family and twin studies have demonstrated that genes contribute towards the development of alcohol dependence, with heritability estimates of between 50 and 60 % for both males and females. McGue, 1999 * Fowler et al, 2007 – found that in a study of 1,214 twins genetic influences played a role in the progression to heavy addiction. * Agravel & Lynsky 2006 – genetic influence with heritability estimates ranging between 45 and 79% * Kender et al, 1998 – 1934 female twins. Drug addiction was mainly due to genetic factor. * Multiple …show more content…
genes are involved and different genes underlie different addictions: Lerman and Commings research indicates this. * A1 Variant of the DRD2 Gene: Individuals with the A1 variant appear to have fewer dopamine receptors in the pleasure part of the brain making it known as the 'Reward Gene' This means that even a little bit of dopamine would cause a lot of pleasure for these people. * A study looking at smokers found that a significantly higher number of smokers had the A1 variant at 48% where as 29% of the rest of the population did.
The Disease Model:
Dopamine system * Dopamine affects pleasure and emotion; addictive substances cause the release of this.
A dopamine pathway is the mesolimbic pathway, which releases dopamine into the limbic part of the brain. People who are prone to addiction naturally have a more sensitive mesolimbic pathway. * Initiation – Research has shown that addictive drugs stimulate a reward circuit in the brain, the drug taking triggers the release of dopamine into the brain which acts as an incentive, effectively telling the brain to ‘do it again’. * Maintenance – Chronic exposure to drugs, alcohol etc. eventually causes a decrease in the activity of these reward circuits, generating a stress situation for the addict, which is usually characterised by withdrawal symptoms or even depression. This negative state becomes dominant and it is this that drives the person to continue their addiction so they do not feel the negative consequences, often leading them to take more as a …show more content…
result. * Relapse – Eventually, the desire to continue the addiction may take over and even though the drug no longer gives any pleasure the brain is still receiving signals forcing the addict to take the drug again.
The frontal cortex has become less effective at making decisions and judging the consequences of action. Also as addicts have learnt to associate the drug with pleasure, any attempts to stop taking it will be difficult as the addict will be surrounded by cues and reminders of the drug which would remind them of pleasure and make them more likely to relapse.
Evaluation of the genetics of addiction:
* Family studies found high rates of alcohol disorders in families. (+) * Someone who is predisposed to alcohol will not be immediately addicted, there has to be an environmental trigger (-) * Lerman found a link between dopamine regulation and tobacco * Noble – Linked D2 to severe alcoholism (but meta-analysis conflicts)(-+) * A1 variant of a gene is higher in alcoholics (+) * A1 version appears to reduce dopamine receptors leading to high risk of alcohol abuse to compensate for lack of dopamine (+) * Whereas some studies such as Nobel (1998) who found alcoholics to be more likely to have the DRD2 Gene, others found no link what so ever or a very weak
relationship * Cocaine and gerorin linked to A1 gene variant (+) * Comings found drugs are linked to different parts of the brain. (+) * Overly reductionist and deterministic (-) * Nature vs. Nurture (-) * Does not explain individual/cultural differences (-)
Evaluation of the disease model: * Studies into smoking and gambling show that brain mechanisims play a role in addiction (supporting evidence eg: Volkow et al, 2001 - Ritilin) (+) * Most of the data is correlational (+) * More research is needed into why people take drugs/gamble but don’t get addicted (-) * Overly reductionist and deterministic (-) * Nature vs. Nurture (-) * Does not explain individual/cultural differences (-)
The genetics of addiction: * People who have an addictive personality are likely to be predisposed to it because of their genes. * Family and twin studies have demonstrated that genes contribute towards the development of alcohol dependence, with heritability estimates of between 50 and 60 % for both males and females. McGue, 1999 * Fowler et al, 2007 – found that in a study of 1,214 twins genetic influences played a role in the progression to heavy addiction. * Agravel & Lynsky 2006 – genetic influence with heritability estimates ranging between 45 and 79% * Kender et al, 1998 – 1934 female twins. Drug addiction was mainly due to genetic factor. * Multiple …show more content…
genes are involved and different genes underlie different addictions: Lerman and Commings research indicates this. * A1 Variant of the DRD2 Gene: Individuals with the A1 variant appear to have fewer dopamine receptors in the pleasure part of the brain making it known as the 'Reward Gene' This means that even a little bit of dopamine would cause a lot of pleasure for these people. * A study looking at smokers found that a significantly higher number of smokers had the A1 variant at 48% where as 29% of the rest of the population did.
The Disease Model:
Dopamine system * Dopamine affects pleasure and emotion; addictive substances cause the release of this.
A dopamine pathway is the mesolimbic pathway, which releases dopamine into the limbic part of the brain. People who are prone to addiction naturally have a more sensitive mesolimbic pathway. * Initiation – Research has shown that addictive drugs stimulate a reward circuit in the brain, the drug taking triggers the release of dopamine into the brain which acts as an incentive, effectively telling the brain to ‘do it again’. * Maintenance – Chronic exposure to drugs, alcohol etc. eventually causes a decrease in the activity of these reward circuits, generating a stress situation for the addict, which is usually characterised by withdrawal symptoms or even depression. This negative state becomes dominant and it is this that drives the person to continue their addiction so they do not feel the negative consequences, often leading them to take more as a …show more content…
result. * Relapse – Eventually, the desire to continue the addiction may take over and even though the drug no longer gives any pleasure the brain is still receiving signals forcing the addict to take the drug again.
The frontal cortex has become less effective at making decisions and judging the consequences of action. Also as addicts have learnt to associate the drug with pleasure, any attempts to stop taking it will be difficult as the addict will be surrounded by cues and reminders of the drug which would remind them of pleasure and make them more likely to relapse.
Evaluation of the genetics of addiction:
* Family studies found high rates of alcohol disorders in families. (+) * Someone who is predisposed to alcohol will not be immediately addicted, there has to be an environmental trigger (-) * Lerman found a link between dopamine regulation and tobacco * Noble – Linked D2 to severe alcoholism (but meta-analysis conflicts)(-+) * A1 variant of a gene is higher in alcoholics (+) * A1 version appears to reduce dopamine receptors leading to high risk of alcohol abuse to compensate for lack of dopamine (+) * Whereas some studies such as Nobel (1998) who found alcoholics to be more likely to have the DRD2 Gene, others found no link what so ever or a very weak
relationship * Cocaine and gerorin linked to A1 gene variant (+) * Comings found drugs are linked to different parts of the brain. (+) * Overly reductionist and deterministic (-) * Nature vs. Nurture (-) * Does not explain individual/cultural differences (-)
Evaluation of the disease model: * Studies into smoking and gambling show that brain mechanisims play a role in addiction (supporting evidence eg: Volkow et al, 2001 - Ritilin) (+) * Most of the data is correlational (+) * More research is needed into why people take drugs/gamble but don’t get addicted (-) * Overly reductionist and deterministic (-) * Nature vs. Nurture (-) * Does not explain individual/cultural differences (-)