Genes associated with addiction

• Drd2 gene: what is the A1 variant of the DRD2 gene associated with?

  • fewer dopamine receptors in the brain’s pleasure centre, leading to compensatory addictive behaviours
• DRD2 gene: what did Comings et Al (1996) find regarding the DRD2 gene and addiction?

  • 48.7% of smokers and ex-smokers carried the A1 variant vs 25.9% of the general population

  • 50.9% of gambling addicts carried the A1 variants vs 25.9% of non-addicts
• ADH and ALDH: what role do ADH and ALDH genes play in addition?

  • They regulate alcohol metabolism, affecting addiction risk
• ADH and ALDH: how do some ADH and ALDH gene variants decrease the risk of alcoholism?

  • increase acetaldehyde levels, causing unpleasant reactions like facial flushing and nausea, discouraging drinking
• ADH and ALDH: how do other ADH gene variants increase the risk of alcoholism?

  • they slow alcohol breakdown, leading to higher consumption and increased consumption risk
• ADH and ALDH: what populations show different alcoholism risks due to ADH gene variations?

  • oriental populations: lower activity ADH genes linked to higher alcohol dependence (Higuchi et Al 2006)

  • European populations: ADH4 variants affect alcoholism risk (Edenberg et Al 2006)