Addictive Behaviour- Biological explanation 2- Addiction Gene

GENETIC FACTORS IN ADDICTION

DRD2

- People with the VI variant of the gene have fewer D receptors in the area that respond to leisure, which means they may try to compensate for it through addictive behaviour.

- 48% smokers had the VI gene (Comings, 1998)

AHD

- ADH and ALDH genes are responsible for the process of metabolising alcohol. Normally the body metabolises it into acetaldehyde due to the enzyme ADH, then another one, ALDH, breaks it down further.

- Some variants can be linked to an increased risk of alcoholism as it takes longer to break down, so they drink more.

- ADH4 variants have been found to effect alcoholism risk in Europe (Edenburg, 2006)

The Diathesis-stress model

- Too simple to say alcoholism is biological alone.

- The model states that addiction only develops when a genetic predisposition to a particular disorder is triggered by an environmental stressor.

- SHTT has been linked to alcoholism, but not on its own. It appears to interact closely with environmental factors such as maltreatment in childhood (Kaufman et al, 2007)

EVALUATION

The difference between initiation and maintenance (✓)

Kendler and Prescott (1998) interviewed nearly 2,000 twins and found that although environmental and social factors would influence whether a person would initiate cocaine use, if they became addicted was more dependant on genetic factors.

Determinism

- (✓) Biological explanations reduce the blame on the addict suggesting they had no control over it.

- (X) If they see addiction as unstoppable, they may less likely to try and recover.

A 'gene' for addiction? (X)

The range of different genes (D2D2, ADH, RSU1 (Ojelade, 2015)) means we can't say there's only one gene.

Role of social and cultural factors (X)

- Often criticized for ignoring other factors

- Boardman et al (2008) studied siblings and twins, and found that although there was a strong genetic component in the onset of smoking behaviour, the rate of daily smoking varied across different schools in the sample.