DOPAMINE AO1

• Biological explanation of addictive behaviour

  Dopamine theory
• Mesolimbic pathway


  • Runs from the ventral tegmental area (VTA) of the brain, to the nucleus accumbens (Nac)
  • Activated whenever we engage in an rewarding activity
  • Creates pleasurable feelings that reinforce a particular behaviour and make us want to do it again, as dopamine is released prompting a 'high' through boosting activity of this brain area
• Many drugs and other behaviours such as gambling, or gaming also cause these reward centres to activate and create the feelings of pleasure that are rewarding and reinforcing
• It is this pleasurable feedback which is at the very heart of addiction
• As the level of emotion experienced in the pathway is so high it explains how an addiction can be formed through repetitive behaviour
• As time goes on, and through repeated usage, the level of drug/behaviour needed to elicit the reaction becomes greater
• Addictive drugs can release two to ten times the amount of dopamine that natural rewards do, and they do it more quickly and more reliably
• In a person who becomes addicted, brain receptors become overwhelmed
• Volkow et al, 1997: 'Research shows that in users of cocaine, there was a reduction in both the number of D2 receptors in the brain and a reduction in the release of dopamine, proving that dopamine must be linked to addiction'
• People who develop an addiction typically find that, in time, the desired substance no longer gives them as much pleasure
• They must take more of it to obtain the same dopamine "high" because their brains have adapted
• Addictive behaviours can change the brain circuits that usually decide what to pay attention to


  The brain attaches too much importance (salience) to the behaviour and the cues associated with it
• Dopamine system plays the role of

  Making the individual want to engage in the behaviour rather than making them like it
• This explains why many addicts report that they no longer enjoy the experience but cannot overcome the craving associated with it