A person’s experiences, genes and environment are all factors
Your chances of developing an addiction depend on what you are like, and what happens to you.
Where you live matters a lot, too – for example, is gambling widespread there? Are drugs available? What are your family’s or culture’s views on addictive substances?
Early exposure to stress or trauma, especially child abuse, is strongly linked with later drug use. Parental drug addiction is also a big risk as it can combine a disrupted childhood, normalisation of substance use, genetic risk factors and access to drugs. Prenatal exposure (where the fetus is exposed to tobacco or drugs while in the womb) has been linked to an increased chance of substance abuse in adulthood. Teenagers may also be influenced by their friends, and be drawn to places where drug use is seen as normal.
Recent research has investigated the role of genetics in a person’s likelihood of trying and becoming addicted to drugs, with some studies suggesting up to 60 per cent heritability of substance addiction. Genetics can play a two-fold role in addiction. Firstly, your genes can influence your behaviour, with risk-taking and novelty-seeking linked to trying substances. Secondly, your genes can alter how you respond to a drug, so may make you more or less susceptible to addiction. Studies of rats have shown that some breeds are more likely to self-administer drugs than others, suggesting genetic vulnerability and genetic resistance to substance use.
There are also strong and complex links between addiction and mental illness. People with bipolar disorder are more than three times as likely to be smokers as those with no mental illness, for example. But do mental disorders put people at risk of addiction, or the other way round? Both might be true. Or maybe other predisposing factors – such as child abuse or genetic variations – leave some people more vulnerable to mood or anxiety disorders and to addictions of various kinds.
What is certain is that addiction and mental illness have a high incidence of comorbidity – where the same person has both, and each affects the other.Lead image:
Redfishingboat (Mick O)/Flickr CC BY NC