The Biological Approach to Addiction

Initiation: AO1

• Addicts inherit a genetic predisposition to developing an addiction
• Multiple genes are responsible for addictive behaviour

• Researchers have focused on the A1 variant of the DRD2 gene - a gene involved in the regulation of dopamine levels

             - This gene may increase sensitivity to the action of dopamine

• More recently researchers have identified specific genes, e.g. SLC6A3-9 (which is responsible for removing dopamine from the synapse) which may also be involved with addiction

Maintenance: AO1

• Addicts inherit a more sensitive mesolimbic dopamine system 
• The mesolimbic dopamine system is: concerned with memory, reward and motivational processes

• Also involved with the maintenance of addictive behaviour

• Normally cells in the mesolimbic dopamine system release small amounts of dopamine to the synapse

• Addictive behaviours and substances increase dopamine levels

• Addicts continue with their addictive behaviour to maintain increasingly high levels of dopamine (tolerance)
• Falling levels of dopamine can lead to unpleasant withdrawal symptoms

Relapse: AO1

• Substances such as nicotine activate the dopamine reward pathway and the brain adapts to be in balance when the substance is present (neuroadaptation) 
• When the substance is discontinued the adaptation is no longer needed and is experiences as withdrawal symptoms which are unpleasant and immediately relieved by using the substance

EVALUATION:

Strengths:

• Research evidence to support the model
• It has lead to effective treatments 
  e.g. Nicotine replacement therapy

Weaknesses:

• Absolves addicts responsibility 
  - Treatment is less likely to work
• Ignores other approaches 
  - Doesn't explain initiation as well as behavioural and or cognitive approach

Application to smoking:

Initiation:

A meta-analysis by Thorgeirsson et al (2008) analysed…