Drugs are chemical substances that can change how your body and mind work. They include prescription medicines, over-the-counter medicines, alcohol, tobacco, and illegal drugs.

Drug use, or misuse, includes:

• Using illegal substances, such as
• Anabolic steroids
• Club drugs
• Cocaine
• Heroin
• Inhalants
• Marijuana
• Methamphetamines
• Misusing prescription medicines, including opioids. This means taking the medicines in a different way than the health care provider prescribed. This includes
• Taking a medicine that was prescribed for someone else
• Taking a larger dose than you are supposed to
• Using the medicine in a different way than you are supposed to. For example, instead of swallowing your tablets, you might crush and then snort or inject them.
• Using the medicine for another purpose, such as getting high
• Misusing over-the-counter medicines, including using them for another purpose and using them in a different way than you are supposed to

Drug use is dangerous. It can harm your brain and body, sometimes permanently. It can hurt the people around you, including friends, families, kids, and unborn babies. Drug use can also lead to addiction.

Drug addiction is a chronic brain disease. It causes a person to take drugs repeatedly, despite the harm they cause. Repeated drug use can change the brain and lead to addiction.

The brain changes from addiction can be lasting, so drug addiction is considered a "relapsing" disease. This means that people in recovery are at risk for taking drugs again, even after years of not taking them.

Not everyone who uses drugs becomes addicted. Everyone's bodies and brains are different, so their reactions to drugs can also be different. Some people may become addicted quickly, or it may happen over time. Other people never become addicted. Whether or not someone becomes addicted depends on many factors. They include genetic, environmental, and developmental factors.

Various risk factors can make you more likely to become addicted to drugs, including:

• Your biology. People can react to drugs differently. Some people like the feeling the first time they try a drug and want more. Others hate how it feels and never try it again.
• Mental health problems. People who have untreated mental health problems, such as depression, anxiety, or attention deficit/hyperactivity disorder (ADHD) are more likely to become addicted. This can happen because drug use and mental health problems affect the same parts of the brain. Also, people with these problems may use drugs to try to feel better.
• Trouble at home. If your home is an unhappy place or was when you were growing up, you might be more likely to have a drug problem.
• Trouble in school, at work, or with making friends. You might use drugs to get your mind off these problems.
• Hanging around other people who use drugs. They might encourage you to try drugs.
• Starting drug use when you're young. When kids use drugs, it affects how their bodies and brains finish growing. This increases your chances of becoming addicted when you're an adult.

Signs that someone has a drug problem include:

• Changing friends a lot
• Spending a lot of time alone
• Losing interest in favorite things
• Not taking care of themselves - for example, not taking showers, changing clothes, or brushing their teeth
• Being really tired and sad
• Eating more or eating less than usual
• Being very energetic, talking fast, or saying things that don't make sense
• Being in a bad mood
• Quickly changing between feeling bad and feeling good
• Sleeping at strange hours
• Missing important appointments
• Having problems at work or at school
• Having problems in personal or family relationships

Treatments for drug addiction include counseling, medicines, or both. Research shows that combining medicines with counseling gives most people the best chance of success.

The counseling may be individual, family, and/or group therapy. It can help you:

• Understand why you got addicted
• See how drugs changed your behavior
• Learn how to deal with your problems so you won't go back to using drugs
• Learn to avoid places, people, and situations where you might be tempted to use drugs

Medicines can help with the symptoms of withdrawal. For addiction to certain drugs, there are also medicines that can help you re-establish normal brain function and decrease your cravings.

If you have a mental disorder along with an addiction, it is known as a dual diagnosis. It is important to treat both problems. This will increase your chance of success.

If you have a severe addiction, you may need hospital-based or residential treatment. Residential treatment programs combine housing and treatment services.

Drug use and addiction are preventable. Prevention programs involving families, schools, communities, and the media may prevent or reduce drug use and addiction. These programs include education and outreach to help people understand the risks of drug use.

NIH: National Institute on Drug Abuse