Addiction is a disease that affects both the brain and behavior. The National Institute on Drug Abuse defines it as “a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences.”

The following answers to common questions about addiction can help you understand the impact of this disease.

Since most people know taking drugs is dangerous and unhealthy, why do they do it?

When they start taking drugs, people are attracted to their perception of the benefits of drugs. Depending on what is being taken, drugs can induce intense feelings of pleasure, power, self-confidence, increased energy, satisfaction, and deep relaxation.

Some people take drugs to relieve stress, to increase their athletic or cognitive abilities, or simply to fit in with a peer group.

As abuse continues, drug abusers often find drug seeking and using takes over their lives. They feel they have to take drugs not to feel “better,” but to feel “normal.”

How do drugs alter the brain, and what are the consequences?

Brain-imaging studies of people who suffer from addiction have found changes in areas of the brain that govern decision making, judgment, learning, memory, and behavior control. According to scientists, these physical changes may explain in part the compulsive and destructive behaviors common among people who are addicted to drugs.

Why do some people become addicted to drugs while others don’t?

People’s risk of becoming addicted depends on a variety of factors, including their biological makeup and their social environment (at home or school, for instance).

Additional risk factors include poor social skills, lack of parental supervision, availability of drugs in their surroundings, mental disorders, unstable family relationships, and exposure to physical and sexual abuse.

How does addiction affect an abuser’s health?

The effects can be devastating. Addiction can increase the risk for heart disease, stroke, cancer, mental illness, and brain damage.

Drug use can also impact the health of others: infants in the wombs of users, for instance, and adults and children who are exposed to secondhand smoke. AIDS and hepatitis C may spread among those who share needles while injecting heroin, cocaine, and methamphetamine.

Knowing more about addiction can help you make informed decisions regarding drug use.