The origins of addiction are quite complex and not fully understood by psychologists. Addiction occurs when people become physically dependent on a substance through repeated use.

Although there is much evidence of the role of dopamine and other neurotransmitters in addiction, psychologists argue that these biological factors work together with and respond to environmental factors, making addiction possible. Two key explanations include Social Cognitive Theory and the role of stress.

Social cognitive theory

Social Cognitive Theory argues that we learn behaviour by observing the behaviour of others. It is important that we identify with the person modeling the behaviour and that we feel that the model has received some positive outcome for the behaviour. This is the concept of vicarious reinforcement.

Bandura also says that self-efficacy is an important part of social learning. In substance use and addiction, it is an important reason why a person may start - or not start - to use a drug. Strong self-efficacy may lead someone to say, "I don't need to use drugs to have fun," or "if I use a drug, I could stop at any time."  Research indicates that this may play a key role in addiction.

One important set of role models is our parents. Bauman et al (1990) found that among American adolescents, if the parents did not smoke, then their children were less likely to smoke. 80% of adolescents whose parents did not smoke had never tried smoking, whereas over 50% of those with parents that smoke did.  Murray et al. (1984) found that in families where the parents were strongly against smoking, the children were up to seven times less likely to smoke.

Peer influences have been found to be among the strongest predictors of drug use during adolescence. It has been argued that peers initiate youth into drugs, provide drugs, model drug-using behaviours, and shape attitudes about drugs. O’Connell et al (2009) suggest that there are three major elements to peer influence as a risk factor for alcohol addiction:

1. An at-risk adolescent’s attitudes and norms about drinking develop by associating with peers who use alcohol

2. These experienced peers then provide more opportunities for the at-risk individual to use alcohol.

3. The individual ends up over-estimating how much their peers are drinking, which means they drink more to keep up with the perceived norm.

Unger et al (2001) carried out a cross-cultural survey of adolescent smoking in a sample of 5143 Californian adolescents with a mean age of 13. The study found that European American students who had close peers who smoked were more likely to smoke than other students (e.g. Asian American and Hispanic students). The researchers explained that in individualistic cultures, adolescents typically create their own youth culture, characterized by rebellion, in order to set themselves apart from their parents. In collectivist cultures, the bond between the teen and the parents is considered important. Rebellion is not tolerated, so adolescents are more likely to conform to the roles and norms that parents prescribe for them.

The role of stress

Stress has an effect on our physiology. These effects may also have an influence on the likelihood of addictive behaviour. Some people smoke or drink as a way of coping, but this may lead to addictive behaviour.  The interaction of environmental stressors and biological dispositions is today an important part of our understanding of addiction. Modern research is particularly interested in the role that adverse childhood experiences may play as a predictor of substance abuse or addiction.

Adverse childhood experiences

There are several studies that show a correlation between the number of adverse childhood experiences and substance abuse or addiction.  Some of the findings include:

• ACE's predict early-onset drinking age (Rothman et al, 2008)
• ACE's are associated with a higher risk of substance abuse disorders later in life (Choi et al, 2017)
• Prevalence of smoking is higher in those with higher ACE scores (Ford et al, 2011)
• For every additional ACE score, the rate of illegal drug use increased up to 4-fold (Dube et al, 2003)

As you can see, there is a lot of research that shows a strong correlation between childhood abuse and later development of drug and alcohol dependency. Cleck & Blendy (2008) found that the longer the abuse continues the greater the chance of dependency. But unlike the well-controlled monkey study by Morgan et al (2002), research on the role of abuse is solely correlational in nature and it is not possible to isolate variables to determine a cause and effect relationship. However, if we generalize the findings from animals, we may perhaps find an explanation for this correlational relationship.