On The Nature Of Addiction
What Happens to Your Brain When You Take Drugs?
There is now scientific evidence to dispel rumors that addiction is a “moral failing.”
Drugs contain chemicals that tap into the brain’s communication system and disrupt the way nerve cells normally send, receive, and process information. Two ways that drugs cause this disruption are by imitating the brain’s natural chemical messengers and by overstimulating the “reward circuit” of the brain.
Some drugs like marijuana and heroin have a similar structure to chemical messengers called neurotransmitters, which are naturally produced by the brain. This similarity allows the drugs to “fool” the brain’s receptors and activate nerve cells to send abnormal messages. This reaction sets in motion a reinforcing pattern that “teaches” people to repeat the rewarding behavior of abusing drugs.
As a person continues to use drugs, the brain adapts to the overwhelming surges in dopamine by producing less dopamine in the reward circuit. This decrease compels the addicted person to keep using drugs in an attempt to bring the dopamine function back to normal, but now larger amounts of the drug are required to achieve the same dopamine high-an effect known as tolerance.
No single factor can predict whether a person will become addicted to drugs. Risk for addiction is influenced by a combination of factors that include individual biology, social environment, and age or stage of development. The more risk factors an individual has, the greater the chance that taking drugs can lead to addiction. For example:
Biology. The genes that people are born with-in combination with environmental influences-account for about half of their addiction vulnerability. Additionally, gender, ethnicity, and the presence of other mental disorders may influence risk for drug use and addiction.
Environment. A person’s environment includes many different influences, from family and friends to socioeconomic status and quality of life in general. Factors such as peer pressure, physical and sexual abuse, and stress can greatly influence the occurrence of drug abuse and the escalation to addiction in a person’s life.
Development. Genetic and environmental factors interact with critical developmental stages in a person’s life to affect addiction vulnerability. Although taking drugs at any age can lead to addiction, the earlier that drug use begins, the more likely it will progress to more serious abuse, which poses a special challenge to adolescents. Because areas in their brains that govern decision making, judgment, and self-control are still developing, adolescents may be especially prone to risk-taking behaviors, including experimenting with drugs.
Source: National Institute on Drug Abuse; National Institutes of Health; U.S. Department of Health and Human Services.