Evaluate one biological explanation (15)

• Point1:

  One biological explanation of addiction is the dopamine hypothesis, which suggests that addictive behaviours increase dopamine levels in the brain‘s reward system. dopamine is released in the nucleus accumbens, creating pleasurable feelings that reinforce the behaviour. This explains why people become addicted to substances like nicotine, which artificially stimulates dopamine production, leading to cravings and withdrawal symptoms when the behaviour stops
• Evidence1:

  Research by Volkow et al. (1997) used PET scans to show that cocaine users had significantly higher levels of dopamine in their brains after taking the drug. This supports the idea that addictive substances increase dopamine activity, reinforcing the behaviour. Additionally, the success of varenicline (Champix), a drug that blocks nicotine from stimulating dopamine receptors, supports the dopamine hypothesis. Smokers who took varenicline experienced fewer cravings, suggesting that reducing dopamine release can help combat addiction.
• Evaluation1

  A major strength of the dopamine hypothesis is its scientific credibility. PET scans and fMRI studies provide objective, reliable evidence of dopamine activity in addiction. Furthermore, dopamine-based treatments, like methadone for heroin addiction, have been effective, showing that targeting dopamine can reduce addictive behaviours. This supports the biological explanation as a useful and practical model for understanding addiction.
• Point2

  Not all addictive behaviours increase dopamine

  However, the dopamine hypothesis is overly simplistic, as not all addictive behaviours are linked to increased dopamine levels.
• Evidence2

  Research by Stokes et al. (2009) found no significant increase in dopamine in cannabis users, despite many developing an addiction. This suggests that addiction may not always be due to dopamine alone. Additionally, Blum et al. (1990)found that some people have a genetic variant of the DRD2 gene, which makes their dopamine receptors less sensitive. These individuals may engage in addictive behaviours not because of excessive dopamine release, but due to a natural dopamine deficiency, leading them to seek artificial stimulation.
• Evaluation2

  This weakens the dopamine hypothesis because it suggests addiction is more complex than just neurotransmitter activity. Psychological explanations, such as classical conditioning (associating smoking with social situations) or cognitive biases (e.g., the illusion of control in gambling), may play a role. This highlights the reductionist nature of the dopamine explanation and suggests that addiction is influenced by a combination of biological, psychological, and environmentalfactors.
• Point3

  Another limitation of the dopamine explanation is methodological weaknesses in research, particularly in lab-based and animal studies.
• Evidence2

  Many studies, like Olds & Milner (1954), showed that rats would repeatedly press a lever for dopamine stimulation, sometimes to the point of starvation. While this supports dopamine’s role in reinforcement, it lacks ecological validity, as human addiction is influenced by social and cognitive factors. Additionally, Libet et al. (1999) found increased dopamine activity in PTSD patients during flashbacks, suggesting dopamine is linked to pleasure-seeking in general, rather than addiction specifically.