Many possible factors have been considered in trying to explain and understand the causes of addiction. One thing is clear: no single factor can be said to cause addiction. People become addicted because of a combination of factors.
It appears that some people may inherit a vulnerability to the addictive properties of drugs. Studies have shown, for example, that the risk of substance use disorders is higher for people who have close relatives with substance use disorders (Glantz & Pickens, 1992). However, many people who have a genetic vulnerability to addiction do not become addicted, and others who do not have a family history of addiction do become addicted.
How drugs interact with the brain
People use alcohol and other drugs because they stimulate the brain in ways that “feel good.” This immediate rewarding experience makes people want to repeat it. All substances with addictive potential stimulate the release of dopamine, a chemical in the brain that is associated with reward and pleasure. Eating, drinking and having sex are all activities that release dopamine. Substance use, however, brings a flood of dopamine, which alters the chemistry of the brain. The brain, in turn, tries to keep things in balance by developing tolerance, which means that more and more of the drug is needed to bring feelings of pleasure. The brain also adapts by decreasing the amount of dopamine available. That’s one reason why people who are addicted report feeling “flat” and depressed without drugs (NIDA, n.d.; Glantz & Pickens, 1992).
The home, neighbourhood or community where people live, go to school or work can influence whether or not they develop substance use problems, as can the attitudes of their peers, family and culture toward substance use. People who experience prejudice, discrimination or marginalization due to culture, race, gender identity, sexual orientation, ability, age or other factors may use substances to cope with feelings of trauma or social isolation.
Mental health issues
Research shows that more than half of people with substance use disorders have also had mental health problems, especially anxiety or depression, sometime in their lifetime (Reiger et al., 1990).
The relationship between substance use and mental health problems is complex. Some people with mental health problems use substances to help themselves feel better, but end up making the situation worse. When people have mental health problems, even limited substance use (e.g., a drink or two) can worsen the problems.
For more information on the relationship between substance use and mental health problems, see the CAMH publication Concurrent Substance Use and Mental Health Disorders. For order information e-mail: firstname.lastname@example.org).
Coping with thoughts and feelings
People may turn to substances as a way of coping with difficult emotions or situations. They may find it hard, for example, to calm themselves down when they feel angry or upset, and come to rely on substances to help them regulate their emotions. People may also use substances to help relieve stress, boredom or sadness, or to reduce their inhibitions and make it easier to talk to others and speak up about feelings.
Spiritual or religious affiliation
Spirituality can mean different things to different people. One aspect that many people experience is a need to feel connected to others and the world around them. People who lack this sense of spiritual connection may feel empty or hopeless. They may use substances to mask these feelings and develop a substance use problem as a result.
Risk and protective factors
Researchers have tried various ways to sort out the complex causes of substance use problems. One way is to ask which factors put people at risk and which protect them from substance use problems. Since substance use often begins in youth, research has focused on this age group.
The risk factors for substance use problems in youth include:
- alcohol or other drug problems among family members
- poor school performance
- poverty, family conflicts, chaos or stress
- having friends who drink or use other drugs
- not fitting in socially, or being excluded because of race, ethnicity, gender, age, sexual orientation, abilities or other factors
- emotional, physical or sexual abuse
- experiencing discrimination or oppression.
The protective factors for substance use problems in youth include:
- having a positive adult role model (e.g., a parent, relative or teacher)
- good parental or other caregiver supervision
- having a strong attachment to family, school and community
- having goals and dreams
- being involved in meaningful and well-supervised activities (e.g., sports, music, volunteer work).
Risk and protective factors do not guarantee that a person will or will not develop problems, but they do affect the level of risk. Once a person has a problem with substance use, risk and protective factors also influence how readily that person is able to change his or her use.