Addiction is a behaviour studied extensively in health psychology.  Addiction can be both physical and psychological and can be related to drugs such as alcohol, nicotine and cocaine – or to behaviours, such as gambling.  Many people argue that addiction is a “choice” and that simple will-power is needed to overcome it. However, psychologists have found biological links to addiction, including both the role of the brain’s reward system and genetics. On the other hand, relying on the biological approach alone is seen as reductionist, ignoring both cognitive and sociocultural factors that may play a role.

Some of the earliest research on addiction took place in the 1950s.  Olds and Milner implanted electrodes into the VTA of rats and found that rats became addicted to pushing a lever that was stimulating their nucleus accumbens.  The electrical stimulation led to the release of dopamine in what Olds called the “pleasure center” of the brain. The rats pulled the lever even if it meant they would go without food.  The same results have been found in humans. Oldfield (2017) found that the nucleus accumbens is highly active when people with gambling addiction experience cravings.

Drugs such as nicotine and heroin cause a surge of dopamine in the nucleus accumbens.  Addiction is linked to the speed with which a drug leads to the release of dopamine, the intensity of the release and the reliability of the release. Repeated exposure to an addictive substance causes the nucleus accumbens and prefrontal cortex to communicate in a way that pairs liking something and wanting something.  This process motivates us to seek out the source of pleasure.

Genetics also seems to play a role in addiction. Ponce et al carried out a study of over 100 alcohol-addicted males. The researchers wanted to see if the men had a variation of the DRD2  gene which codes for the number of dopamine receptors in the reward system. People with fewer dopamine receptors need higher levels of dopamine to produce the same effect as people with more receptors and are more prone to addiction. The study found that 40% of the sample had the genetic variation and that they had a higher prevalence of alcoholism in the family. Although the results are significant, the study leaves us wondering about the other 60%.

There are limitations of genetic research on addiction which may help to explain that. First, there is the question of how “addiction” is operationalized in a study. The participants that volunteer for the studies report both their own level of addiction and the addictions of their twins or other family members.  This means that the “measure” of addiction among all participants is not standardized. This may also be why there is not a high level of reliability in genetic research on addiction. Genetic research has also found differences depending on the drug or behaviour.  It is not clear if there is something about the nature of the drug that leads to these differences, or limitations of the research itself.

Genetic arguments are seen as deterministic, taking away the free choice of the individual.  It is as if one is “destined” to be an addict.  It is unclear how a gene would actually lead one to start taking a drug.  And this is why social factors are important to consider when discussing addiction.

Research shows that there is a link between stress and addiction. Research with monkeys shows that monkeys that are lower in the social hierarchy have fewer dopamine receptors, meaning that they would have a higher rate of addiction if given cocaine. In humans, Clerk & Blendy (2008) found that the longer a child experiences abuse, the greater the chance of drug addiction later in life.  These studies do not challenge the biological argument, but they show that a biopsychosocial approach may be more relevant.

Finally, Social Cognitive theory argues that drug use can be learned by watching others  - through a process called vicarious reinforcement. In a study carried out in the USA, Bauman found that if the parents smoke, the children are more likely to smoke. 80% of adolescents whose parents did not smoke never tried smoking, but over 50% of children with smoking parents did. This is not limited to parents – adolescents smoke more if their peer group smokes.

The social cognitive theory does not, however, explain addiction – it explains why people choose to start using the drug. But once again, it is most likely biological factors that decide whether a person who starts smoking will become addicted to nicotine. In addition, much of the environment and social research that is done is correlational in nature since experiments of this nature would be unethical.  The biological approach allows for cause and effect experiments, at least in the study of animals. However, correlations seen in human research appear to confirm much of the animal research. It appears that biological factors are a necessary component of addiction that are triggered through one’s social situation.