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Biological models of addiction
Emphasize influence of genetic & neurochemical in onset & maintenance of addiction. A
-It's a specific diagnosis (cant be slightly addicted). -The problem lies in the individual
-Its an illness which is irreversible -There is an emphasis on treatment
Some believe that people who show addictive behaviour have an underlying abnormality
such as AA who take this view and see addiction as an allergic response. There is little
evidence for this view but there is support for the idea that genetics may play a role.
The genetics of addiction
-Family and twin studies - have shown that genes contribute to the development of
alcoholism with heritability levels between 50-60% for both men and women. A study found
illicit drug abuse was also affected by genetic influence, with heritability estimates ranging
from 45-79%. Adoption studies support the theory as they found that even children who
were separated from their biological parents showed tendencies for addiction showing
importance of genes as well as environment.
-Specific genes 90's research into D2 dopamine receptor gene (DRD²) linked it to severe
alcoholism. Noble et al found that A1 variant of the gene was present in more than 2/3rds of
deceased alcoholics compared to 1/5 of deceased non-alcoholics . Noble went on to label it
as the `reward gene' and found those who inherit it are more likely to become addicted to
drugs that increase dop levels are it compensates for the deficiency and they need it to feel
good, causing them to become addicted. Comings et al found that 48.7% of group of
smokers and ex-smokers had the gene compared to 25.9% of the normal population.…read more
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The disease/biological model (neurochemical)
Initiation Research has shown addictive substances stimulate the reward circuit
in the brain, specifically the mesolimbic pathway and endogenous opiod system.
Rewarding experiences trigger the release of abnormal amounts of dopamine
which tells the brain to do it again. It's been suggested that those who may be
vulnerable to addiction are born with more sensitive mesolimbic pathways.
Maintenance Chronic exposure to harmful addictive substance will eventually
cause a reduction in the activity of the reward circuits known as down regulation.
These changes to the brain structure, caused by the addictive behaviour
contribute to the tolerance, dependence and cravings associated with addiction.
This causes withdrawal symptoms, and anxiety which forces the addictive to
feed the drug craving, not to seek pleasurable experiences but fulfil the need to
avoid the unpleasurable state which in when the individual becomes tolerant.
Relapse Eventually desire to get the drug takes over and becomes more
important than anything, even though the drug no longer gives much if any
pleasure. This makes permanent recovery very hard to achieve as they have
learnt to be rewarded by it and are surrounded by cues which act as reminders of
the reward the drug brings. The frontal cortex has become less effective in
making decisions which heightens the risk of relapse.…read more
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Evaluation of genetic factors
·Genetic explanations can explain why some people are more likely to become addicted
than others and then go on to resist treatment and be more likely to relapse.
·Noble found that 48% of severe alcoholics, 32% of less severe alcoholics and 16% of
controls are carriers of the DRD² gene supporting the idea genes do affect vulnerability to
addiction. However subsequent studies have failed to find this relationship suggesting it
may lack validity.
·The findings of Coming et al's study that smokers were more likely to have the gene has
a flaw because the gene has also been found in 45% of Tourrete's patients compared to
25% of normal pp's, and Tourrete's sufferers aren't normally perceived as pleasure
Evaluation of biological model
·Supporting evidence: Volkow et al conducted research in which pp's were given drug,
which lifts dopamine levels, and found some liked the rush and some didn't. Those who
did had more dopamine d² receptors, suggesting they're vulnerable to the rush, and
explains why some people who experiment with drugs may go on to become addicted and
not others. Caine et al found that mice who didn't have the d² receptor didn't self-
administer cocaine suggesting dopamine is important in addiction, but these results can't
yet be generalised to humans.
·Reductionist Reduce complex idea to simple level explanation, ignoring environmental
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Cognitive models of addiction
Emphasize the processes that control mental function and looking at events which make
lead to addiction, and see's addiction as a coping mechanism for life's problems.
The self-medication model
Initiation People intentionally use drugs to treat psychological symptoms, and use
specific ones to treat specific symptoms. Therefore initiation depends on the individual
and their needs. The drug may not make things better, but if the person judges them to be
working, they will become addicted. It helps with mood regulation, performance
management and distraction.
Maintenance & Relapse Stress relief is a common reason for smoking, even though it
doesn't actually relieve long term stress. However it does relieve the short term stress of
withdrawal symptoms so the addict believes it is helping, explaining the maintenance of
addiction. If they give up the stress returns and makes it's impossible to quit, so they
relapse to relieve the even higher stress levels.
Evaluation Research support comes from Gottdiener et al who carried out a meta-
anlaysis to test whether addiction is associated with failures of ego control (regulate
control over impulses to self medicate). Found that pp's with substance abuse disorders
showed significant failures in ego control compared with the control group. However the
model doesn't explain addiction where there are no major psychological problems to
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Addicts differ from non-addicts in terms of their expectations about the positive
and negative effects of an addictive behaviour.
Initiation Alcohol use/addiction escalates depending on the expectations an
individual has about the positive and negative effects of a behaviour. Heavy
drinkers have been shown to have more positive expectations of the effects of
alcohol than light drinkers, such as tension reduction, greater sociability and
Maintenance & relapse As an addiction develops it becomes less affected by
the conscious expectations and more by unconscious expectations, as processing
becomes more automatic. This explains the loss of control many addicts face and
the difficulty in quitting. However expectations have been found to prevent
relapse when manipulated in a study in which pp's were told to expect no
negative experiences. They had few somatic effects (shakes) and psychological
effects (mood swings) than the control group.
There may be a publication bias as much of the research is positive and there isn't
much attention on undermining evidence. The model also doesn't really consider
addiction, but more consumption because if addiction is a loss of control, than
what does expectations have to do with it? However a plus of the model is that it
isn't deterministic as it accounts for the thinking process and free will in choosing
to become addicted or not.…read more