Outline two biological explanations for addictive behaviours

• Point


  One biological explanation for addiction is the role of dopamine in the brain’s reward system.
• Evidence 1

  The mesolimbic pathway, which includes the ventral tegmental area (VTA) and the nucleus accumbens (NAc), is responsible for feelings of pleasure and reinforcement. Engaging in addictive behaviours or consuming addictive substances triggers the release of dopamine in this pathway, creating a rewarding sensation. Research has shown that gambling and alcohol both increase dopamine levels (Joutsa et al., 2012; Boileau et al., 2003). However, over time, dopamine receptors become less sensitive, leading to tolerance and the need for greater engagement in the addictive behaviour to …
• Evidence 2

  … achieve the same effect (Volkow et al, 1997). If the individual stops, they may experience withdrawal symptoms, reinforcing continued addictive behaviour
• Explain

  This suggests that addiction is driven by changes in the brain’s dopamine system. Initially, individuals may engage in addictive behaviours for pleasure, but over time, their behaviour is maintained to avoid withdrawal rather than to seek pleasure. Additionally, changes in the frontal cortex can lead to cravings and compulsive drug-seeking, even after withdrawal symptoms have subsided (Robinson & Berridge, 2003).
• Link

  Therefore, addiction can be explained biologically through dopamine dysregulation, which reinforces engagement in addictive behaviours and contributes to cravings and relapse.
• Point

  Another biological explanation for addiction is genetic inheritance, which suggests some individuals are more vulnerable to addiction due to their genetic makeup.
• Evidence 3

  Research has shown that addiction is moderately to highly heritable, with heritability estimates ranging from 39% for hallucinogens to 72% for cocaine (Goldman et al, 2005). a specific gene implicated in addiction is the DRD2 gene, which affects dopamine receptors. Individuals with the A1 variant of the DRD2 gene have fewer dopamine receptors in the brain’s pleasure centre, making them more likely to seek stimulation through addictive substances or behaviours. studies have found that 48.7% of smokers and ex-smokers carry the A1 variant compared to only 25.9% of the general …
• Evidence 4

  … population (Comings et al., 1996). Additionally, the ADH and ALDH genes, which influence how the body metabolises alcohol, have been linked to alcoholism. Some variants of these genes slow down alcohol metabolism, increasing the likelihood of excessive drinking and dependence (Higuchi et al., 2006; Edenberg et al., 2006).
• Explain

  This suggests that addiction is partly determined by genetic predisposition. Individuals with genetic variations affecting dopamine levels may be more likely to develop addictive behaviours as they seek ways to compensate for a less responsive reward system. Additionally, genetic differences in alcohol metabolism can influence drinking behaviour and the risk of alcoholism.
• link

  Therefore, genetic factors play a key role in addiction by influencing brain chemistry and an individual’s likelihood of engaging in addictive behaviours.