A- Biological explanations Flashcards
what is the first biological explanation of addiction
dopamine
what do addictive behaviours and substances trigger
a release of dopamine in the mesolimbic pathway
what is the mesolimbic pathway responsible for
the reward sensation, pleasurable activities such as eating but also drug taking trigger the release of dopamine which basically tells the brain to do it again
explain how crack cocaine has an affect on the brain
causes a massive and rapid activation of dopamine receptors in the mesolimbic pathway, creating a lasting memory that link that drug to a pleasurable reward
who proposed incentive sensitisation theory and what is it
robinson and berridge
repeated exposure to drugs of abuse leads to increasing sensitivity of the brain which can persist even without continued exposure of the drug
explain maintenance
continued exposure to to the drug eventually results in a reduction of the activity of these positive reward circuits in the brain (downregulation) as the dopamine receptors become less sensitive to the effects
what happens as a result of downregulation
a chronic stress situation for the addict (withdrawal symptoms, sadness and anxiety) this than causes the drug craving, may no longer enjoy the drug taking but do it to avoid the withdrawal symptoms. the addict also becomes tolerant
explain relapse (dopamine explanation)
the desire for drugs becomes the most important desire, despite the drug no longer providing much pleasure the brain is still receiving signals of reward that force the addict to relapse and take the drug again
why is permanent recovery made more difficult
due to the drug-induced changes in the frontal cortex that creates a lasting memory of the drug
\explain the frontal cortex’s link to addiction
area of the brain liked to cognitive functioning (decision making and memory) addicts have learned to expect a rewarding experience from the drug, when the individual tries to withhold from the drug the constant release of dopamine predicts a reward, this happens even if the addict knows the rewards isn’t coming because their self control has weakened. the frontal cortex has become less effective at making decisions and judging the consequences of their actions. this heightens the risk of relapse
one strength of the dopamine explanation
practical applications, positive effective treatment for addictive behaviours
evidence to support practical applications of addiction
Botswick and Bucci
treated a young adult male patient who was addicted to sex. he had a strong appetite for pornography, engaged in phone sex in his teens and in his 20s would spend hours searching for ‘sexual gratifying activity’ he was treated with nalextrone which effectively blocked the release of dopamine associated with the sexual activities. blocking the reward stopped the power of his addiction, his psychosexual functioning dramatically improved
what does Botswick and Bucci’s research suggest
that the drug therapies created as a result of this explanation can go some way to improving the lives of real people
a second strength of the dopamine explanation
theres supportive evidence which can account for individual differences in addiction
evidence to support individual differences in addiction
Volkow et al gave Ritalin (which gently lifts dopamine levels) to a group of volunteers. some of them loved the feeling of the drug and others hated it. they then produced scans of their brains and found that those who liked the rush from the drug had fewer dopamine receptors compared to those that hated it,
what did Volkow et al conclude from his research
that some people are particularly vulnerable to the rush given by dopamine enhancing drugs, but others cannot take further stimulation
what does Volkows research suggest/explain
this could explain why some people after experimenting with drugs, might go on to develop an addiction whilst others may not (even with the same initial experience) this seems to be the case of real world human behaviour so supports this biological explanation
a weakness to the dopamine explanation
not all addictions seem to increase dopamine levels, although there is significant evidence to demonstrate the increased levels of dopamine following the consumption of some drugs, this is not the case for all addictive behaviours and substances which cannot be ignored
researchers that don’t agree with this explanation due to not all addictions showing increased dopamine levels
Stokes et al. found no significant increase in levels of dopamine in volunteers taking cannabis
Yoder et al. found no consistent increase in dopamine across the participants in their study who were given alcohol
what does Yoder and Stokes research suggest
we must proceed with caution before suggesting all addictions can be put down to the action of dopamine on the brain when this is not the case
another weakness of the dopamine explanation
explaining addiction as being down to dopamine alone is too simplistic and fails to recognise that dopamine has a range of other functions besides providing a reward sensation
research to support the dopamine explanation being too simplistic
(2 pieces)
Bell refers to dopamine as the ‘Kim Kardashian of neurotransmitters’ suggesting it has become fashionable to blame dopamine for causing a range of problems, whereas the actual brain systems that must be involved will be many and varied
studies have also suggested that dopamine levels also increase in the presence of unpleasent stimuli, Lierzon et al showed increased activation in the mesolimbic pathway of war veterans suffering from PTSD when reminded of battle through combat sounds.
what does Bell and lierzons research suggest
these findings are in direct opposition to what we would predict about dopamine if we are to believe that it is the cause of addictive behaviour therefore weakening the explanation.
what is the second biological explanation of addiction
genes
