Biological Explanation - Dopamine Flashcards
Mesolimbic pathways
Reward pathway
Consist of: ventral tegmental area - release dopamine when accomplished tasks (eating, finishing work)
Nucleus accumbens - pleasure it felt when it present of dopamine
Negative addictive acts also activate this system
Joshua et al - dopamine level up in participants during gambling task whether or not win
Lead to salience - addiction becomes hobby
Tolerance + withdrawal
When exposed to drug - brain train to regain equilibrium to remain normal function - neuroadaptation (brain develop more receptors)
-if use repeatedly presence of drugs becomes the norm = changes in brain considered normal
Volkow et al - cocaine user has reduced D2 dopamine receptor + less dopamine released
If no drugs = brain not in equilibrium
-cause withdrawal effect - want to take drugs to go back to normal - take a long time for brain to adapt to no drug
-no take for pleasure, take for avoid withdrawal
Role of frontal cortex
Volkow et al - excess dopamine release cause abnormalities in frontal cortex, change attention ability - pay more attention to stimuli associated with addiction
Robinson and Berridge - addict feel compelled to do addiction even when no pleasure - explain relapse - instinct to carry out addiction
Evaluation - causal relationship
Can explain how individual progressively become addicted - develops tolerance + withdrawal
Explain relapse - by brain abnormalities
Allow for therapies to be developed - drugs
Contradicting evidence
Stokes et al - no significant change in dopamine lvl in participant who took cannabis
-not as credible, may be other variables are problem (environment or role of gene)
Ignore individual difference
Does not explain why some people more likely to be addicted or not
-if dopamine only explanation = everyone react same way to drugs
A1 variant of DRD2 gene - link with D2 dopamine receptor
-those with lower activity less receptor = less stimulated - more likely to indulge more in addiction since more tolerant
