Addiction: Biological Approach

Biological Approach to Addiction

Initiation:

• Addicts inherit genetic predisposition to developing an addiction. 
• Multiple genes involved - particularly A1 variant of DRD2 gene (involved in regulation of dopamine levels). This increases people's sensitivity to action of dopamine.
• SLC6A3-9 gene (removes dopamine from the synapse) involved in addiction.

Maintenance:

• Meso-limbic dopamine system - to do with memory, reward and motivational processes - involved with maintaining an addictive behaviour.
• Normal activity = cells in meso-limbic dopamine system release small amounts of dopamine into the synapse. 
• Addictive substances and behaviours increases dopamine levels in synapse.
• Addicts continue addictive behaviour because in order to experience highs from the addiction, they need to maintain high levels of dopamine (tolerance) 
• Falling levels of dopamine = withdrawal symptoms
• People more susceptible to addictions may have inherited a more sensitive meso-limbic dopamine system.

Relapse:

• Substances (e.g nicotine) activate dopamine reward pathway and brain adapts to be in balance when substance is present (neuroadaptation) 
• When substance discontinued, neuroadaptation no longer needed = withdrawal symptoms (unpleasant, immediately relieved by using substance)

Evaluation of the Biological Approach

• Compared with other approaches the biological model does not explain initiation as well as the behavioural and/or cognitive approach
• Has led to effective treatments e.g Nicotine Replacement Therapy for smoking
• Absolves addicts of responsibility - if the causes of addiction are due to genes or dopamine levels, this means the addict is releived of responsibility for the addiction so treatment is less likely to…