Any child or teenager with access to alcohol or drugs can potentially develop a substance-use problem. But some are at greater risk. Genetic vulnerability plays a strong role, and substance disorders run in families. But there are modifiable factors - influences that can be changed - that are important, too. Studies show that teenagers are more likely to develop substance disorders if they have depression, low self-esteem, or the feeling that they don't "fit in" socially. Other modifiable factors include substance availability, price, and family and cultural attitudes.

All these influences play a cumulative role. Genes interact with environmental factors. But modifying some risks can help offset the impact. For instance, there is a "spectrum of risk." If a teenager has more than one risk factor, substance use can spin out of control. First comes "recreational use," and then binging. Substance Abuse may evolve into Substance Dependence. This risk is especially high with drugs - such as cocaine or heroin - that have a high potential for abuse, tolerance, and withdrawal.

Genetic factors: Biology, an inborn vulnerability, is probably the most important risk factor. A family history of alcohol and drug abuse increases the chances that a child will also develop a problem. Alcohol dependence is four times more likely if a close relative has the problem. This genetic link is so strong that if biological children of alcohol-dependent parents are adopted and raised by non-addicted adoptive parents, the children are still at greater risk for an alcohol problem. Among twins, the chance for alcohol dependence occurring in both twins is higher for identical twins than for fraternal twins.

Family role models: Parental disapproval has a strong protective effect. Family attitudes have been shown to affect kids' substance-use behavior. Studies report that rates of marijuana, alcohol, or cigarettes are lower among teenagers who believe their parents would strongly disapprove than among those who thought their parents did not care. Parents can provide positive role models and encourage discussion on the risks of alcohol and drug use. They can also reduce risk by making sure that unmonitored supplies of substances are not available in the home.

Social and peer pressure: Peer pressure affects all children and adolescents. Kids want to "fit in." Friends and the media can pressure them to consider alcohol or drugs appealing. Curiosity also plays a role. But like adults, teenagers may also use alcohol and drugs to self-medicate. The effects may feel good, temporarily. Teenagers may also be trying to cope with stress and painful experiences. Or they may simply be bored.