Addiction- biological approach

HideShow resource information
  • Created by: Izzy
  • Created on: 22-11-15 16:03
View mindmap
  • Biological approach
    • Sometimes referred to as 'disease models'
    • Assumptions
      • Addiction is an illness
      • The problem lies in the individual
      • There should be an emphasis on treatment
    • Some biologists believe people showing addictive behaviour may have biological predisposition
    • Genetics
      • Unlikely addictive behaviour is due to single gene
      • Family studies of alcohol use have shown high rates amongst relatives
        • Merikangas et al: 36% of relatives had also been diagnosed with alcohol use disorder
        • Impossible to separate out the effects of genetics and environment
          • Adoption studies also lend support to genetic component.
            • Kendler et al: heritability of nicotine dependence estimated at 60-70%
            • Heath and Martin: Heritability ofalcohol dependence 39-60%
      • Even if genetic component identified, would still be necessary to determine mechanism.
        • Could be biochemical or psychological
      • Predisposition to addiction will only express itself if the individual consumes large amounts of the substance
        • Triggers to start probably result from environmental factors
    • Biochemical factors
      • Different substances have different effects on the brain but two major pathways have been identifies in development of substance abuse
        • Dopamine reward system (mesolimbic dopamine system)
          • In normal dopamine activity cells in the mesolimbic dopamine system is spontaneously active, releasing small amounts of dopamine into the synaptic cleft and is probably responsible for maintaining stable mood states
            • Research has shown that both alcohol and nicotine affect the nervous system by increasing dopamine levels.
            • Rewarding experiences such as drug taking, trigger the release of the brain chemical dopamine , effectively telling the brain to do it again
          • It has been suggested that people susceptible to addiction may have decreased response to normal rewards
          • Research has shown that addictive drugs stimulate a reward circuit for the brain
            • Rewarding experiences such as drug taking trigger the release of dopamine, effectively telling the brain to do it again
              • Chronic exposure to the addictive substance results in the reduction in the activity of these positive reward circuits
                • this generates a chronic stress situation for the addict, characterised by withdrawal symptoms
                  • This negative state them becomes the dominant force driving drug craving. Positive reinforcement  becomes negative reinforcement.
                • permanent recovery is made difficult as the drug induced changes create lasting memories of the drug
                  • have learnt to expect a rewarding experience from the drug, the individual trying to abstain is surrounded by cues
                  • Capaccity for self control is weakened, the frontal cortex has become less effective at making decisions and judging consequences
        • Endogenous opioid system
          • It has been observed that patients who are obsessive are characterised by high metabolic rates in the frontal area of the brain, and by high seratonin levels.
            • Opoid neurotrasmitters in the brain include  enkephalin and endorphins
            • The opioid systems are activated in states of pleasure , and can be directly stimulated  by addictive drugs.
      • Neurotransmitters are brain chemicals necessary for the transfer of information within the nervous system
        • Dopamine has received special attention from addiction research due to its role in regulation of mood, emotion, motivation and reward processes.
      • Most the time humans exercise some choice over which behaviours they engage in. May overindulge but soon revert to more moderate pattern
        • Because of ability to balance two competing neurochemical systems
          • Reward reinforcement system tells us eating/drinking is pleasurable and a control system tells  us when we have had enough
            • It appears seratonin plays an important role in this control
              • Seratonin levels are lower in people who are impulsive
              • Patients who attempt compulsive suicides and impulsive homicidal behaviour; as well as those with severe early onset alcoholism and bulimia , all have low seratonin levels


No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Addictive behaviour resources »