Do You Know Your Risk for Addiction?

First published 2008. To view the latest Heads Up content, click here.
What is drug addiction?
Addiction is defined as a chronic and relapsing, yet treatable, brain disease characterized by compulsive drug seeking and use, despite negative or harmful consequences. Drug addiction is considered a brain disease because drugs change the structure of the brain, as well as how the brain works. It is similar to other diseases, such as heart disease, in that it disrupts the normal, healthy functioning of the organ (the brain). Like other diseases, drug addiction can have serious harmful consequences, but it is also preventable and treatable.


How do drugs affect the brain?
Drugs are chemicals that interfere with the way nerve cells normally communicate in the brain. All drugs target the brain’s reward system by increasing the release of dopamine, a chemical linked to pleasurable experiences, such as eating. The excess dopamine produces the “high” that makes a person feel good and teaches him or her to repeat the behavior. Over time, the brain adjusts to the excess dopamine, and the person can no longer experience pleasure in normal ways—they need the drug to feel good. Other parts of the brain become involved as well, including those associated with memory and self-control. Eventually, nothing else can compete with the drug experience. Food, family, and friends lose their former value, while the need to seek and use drugs becomes all-consuming—this is the essence of addiction.

Drug addiction is a complex disease that has serious, harmful effects on a person’s health and on his or her social relationships. How does a person become addicted to drugs? The answer is not so simple—no single factor determines whether a person will become addicted to drugs. Drug addiction is defined as a treatable brain disease that makes it difficult to resist drug use. The risk factors that contribute to addiction are biological or environmental, or many different combinations of both types of factors.



Research shows that drug abuse usually begins in adolescence. There are several reasons for this. For one, the parts of the brain that control judgment, self-control, and future planning do not fully mature until young adulthood. As a result, the teen brain is wired for risk-taking and experimenting. Trying new things is part of the process of maturing and developing the brain’s ability to evaluate risk and make decisions. Another important reason why drug use frequently begins in adolescence is that teens are often strongly influenced by their peers, who may convince them that “everybody’s doing it.”The good news is that teens can control factors that put them at risk of engaging in harmful behaviors, such as drug abuse. However, in order to do so, teens need to understand what those risk factors are.



Biological Factors

A person’s unique biology—his or her genes, age, gender, and other factors—plays a role in his or her risk of experimenting with drugs and becoming addicted. Biological factors that can contribute to someone’s risk for drug abuse and addiction include:

  • Genetics.  You may have heard that drug and alcohol addiction can run in families. This is true, but just because someone in your family has struggled with addiction does not mean that you are destined to do the same. However, having a family member who has experienced addiction does mean that a person may be at increased risk of becoming addicted if he or she chooses to take drugs in the first place. Genes, combined with other factors, are estimated to contribute about 40%–60% of the risk for drug addiction.

  • Developmental stage. Research shows that the earlier a person begins to use drugs, the greater the risk for addiction later in life. There are likely many reasons for this, but one is that the human brain undergoes dramatic changes during adolescence, which continue into early adulthood. Teens’ brains are especially at risk because they are still maturing. Drugs exert long-lasting influences on a developing brain that can increase a person’s vulnerability to later drug abuse and addiction.

  • Sensitivity to drugs. Have you ever noticed how some people can drink a caffeinated beverage and it has no effect on them, while others are bouncing off the walls and can’t sleep? People have different sensitivities to a drug’s effects—in fact, what one person likes, another may hate. These differences affect the likelihood that someone will continue to take drugs and become addicted to them.

  • Mental illness. Mental disorders, such as depression, anxiety, attention deficit hyperactivity disorder (ADHD), and others, may put people at greater risk for using drugs and becoming addicted. There are many possible reasons for this increased risk for addiction. One is that some people with mental disorders take drugs because the drugs make them feel better, or they believe the drugs help them deal with their problems. Also, mental disorders affect the same brain circuits and chemicals as do drugs of abuse. The overlapping effects of a mental disorder and a drug may increase the risk for addiction.

  • Gender.  Studies show differences in the way drugs affect male and female bodies, as well as how and why men and women use drugs. For example, women are more likely than men to become addicted to drugs designed to treat anxiety or sleeplessness, while men are more likely than women to abuse alcohol and marijuana. In the past, studies showed that, overall, there was a higher rate of drug use and addiction among men than among women. However, in recent years, this gender gap is closing—current studies show that equal numbers of male and female teens are reporting that they are using drugs. The consequences of this shifting pattern remain to be seen

  • Ethnicity.  Ethnicity is a factor that has both biological and environmental components. For instance, some ethnic groups show different rates of metabolism of drugs (how drugs are broken down by the body), which can affect drug sensitivity. But there are also cultural factors that influence drug use, and societal factors that impact the consequences of drug use. For example, while overall drug use by African-Americans and Hispanics is lower compared to white Americans, the consequences—such as trouble with the law or risk for disease such as HIV/AIDS—disproportionately affect minorities.


Environmental Factors

Environmental factors are related to a person’s surroundings and the influences he or she lives with. Environmental factors that can contribute to someone’s risk for drug abuse and addiction include:

  • Home and family.  The home environment has an important impact on a person’s risk for drug abuse and addiction. Teens are at greater risk if they live in chaotic homes where there is little parental or adult supervision. This type of home environment can be the result of parents or older family members who suffer from a mental disorder, engage in criminal behavior, or abuse drugs or alcohol. On the other hand, a nurturing home environment, as well as clear rules of conduct at home, can be protective factors that reduce the potential for drug abuse.

  • Availability of drugs.  Research has clearly shown that the availability of drugs in a person’s home, school, or community is one of the key risk factors for a person developing drug problems. For example, the abuse of prescription drugs, which has been on the rise for the last several years, is occurring at the same time as a sharp rise in medical prescriptions. This increased availability, combined with a lack of understanding about the dangers of misusing prescription drugs, affects the risk of addiction.

  • Social and other stressors.  Stress, and particularly early exposure to stress, is linked to early drug use and later drug problems. For example, stressors such as physical or sexual abuse, or witnessing violence, may contribute to someone’s risk for addiction. In addition, poverty is often linked to stress, and to chaotic lifestyles, which may increase the risk for drug abuse. In contrast, involvement in social networks that are supportive, and where disapproval of drug use is the norm, can protect against drug use. These groups might be sports teams, religious groups, or community groups.

  • Peer influence.  Associating with peers who engage in risky behaviors and who use drugs is another key risk factor, especially for teens. Choosing friends who do not use drugs can protect a person from drug abuse and addiction.

  • School performance.  Academic failure may be a sign that a teen is currently abusing drugs and is in need of intervention, or it may be a risk factor for later drug abuse. On the other hand, teens who are successful in school, have positive self-esteem, and develop close bonds with adults outside their families (such as teachers) are less likely to abuse drugs.


Learn more about genetics and addiction.

(Header image credit: © Pixland/Corbis Photography)

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