Genetic explanations

• Twin studies suggest genes predispose offenders to crime
• Lange studied 13 MZ and 17 DZ twins where one of the twins in each pair spent time in prison. Ten of the MZ twins has a co-twin who was also in prison but this was only true for two of the DZ twins
• More recent research by Christiansen found a concordance of 33% for MZs and 12% for DZs which supports the view that offending may have a genetic element
• Two examples of candidate genes:

  MAOA and CDH13
• A genetic analysis of 900 offenders by Tilhonen et al. revealed two genes that may be associated with violent crime, MAOA and CDH13. This high-risk combination led to individuals being 13 times more likely to have a history of violent disorder
• MAOA gene:

  controls serotonin and dopamine and is linked to aggressive behaviour
• CDH13 gene:

  linked to substance abuse and ADHA
• Diathesis-stress model:

  If genes have an influence on offending, this influence is likely rooted in be at least partly moderated by environmental factors
• Diathesis-stress model:

  A tendency to criminal behaviour may come about through a combination of:

  • Genetic predisposition (diathesis)
  • A biological or psychological stressor or 'trigger' (e.g. criminal role models or dysfunctional upbringing)