Some people smoke marijuana in hand-rolled cigarettes called joints. Many use glass pipes, water pipes called bongs, or marijuana cigars called blunts (often made by slicing open cigars and replacing some or all of the tobacco with marijuana). To avoid inhaling smoke, some people are using vaporizers. These devices pull the active ingredients (including THC) from the marijuana into the vapor. A person then inhales the vapor, not the smoke. Some vaporizers use a marijuana liquid extract. Marijuana can also be brewed as tea or cooked into food, sometimes called edibles—such as brownies, cookies, or candy.

These concentrated extracts made from the marijuana plant should not be confused with “synthetic marijuana,” sometimes called “K2,” “Spice,” or “herbal incense.” These synthetic drugs are man-made chemicals similar to THC but often much stronger and very dangerous. (Unlike marijuana, their use sometimes directly results in overdose deaths. Learn more about “synthetic marijuana”.

When marijuana is smoked or vaporized, THC quickly passes from the lungs into the bloodstream, which carries it to organs throughout the body, including the brain. Its effects begin almost immediately and can last from 1 to 3 hours. Decision making, concentration, and memory can be affected for days after use, especially in regular users.² If marijuana is consumed in foods or beverages, the effects of THC appear later—usually in 30 minutes to 1 hour—and may last for many hours.

As it enters the brain, THC attaches to cells, or neurons, with specific kinds of receptors called cannabinoid receptors. Normally, these receptors are activated by chemicals similar to THC that occur naturally in the body. They are part of a communication network in the brain called the endocannabinoid system. This system is important in normal brain development and function.

Yes, marijuana can be addictive. Someone who regularly uses marijuana may continue to use it despite negative consequences in their life.

Approximately 10 percent of users may develop what is called a marijuana use disorder—problems with their health, school, friendships, family or other conflicts in their life. A serious substance use disorder is commonly called an addiction. The person can’t stop using marijuana even though it gets in the way of daily life.⁹ People who begin using marijuana before the age of 18 are 4–7 times more likely than adults to develop a marijuana use disorder.¹⁰

What causes one person to become addicted to marijuana while another does not depends on many factors—including their family history (genetics), the age they start using, whether they also use other drugs, their family and friend relationships, and whether they take part in positive activities like school or sports (environment). More research needs to be done to determine whether people who use marijuana for medical reasons are at the same risk for addiction as those who use it recreationally.

When teens drink, alcohol affects their brains in the short-term– but repeated drinking can also impact it down the road, especially as their brains grow and develop.

Short-Term Consequences of Intoxication (being “drunk”):

• An intoxicated person has a harder time making good decisions.
• A person is less aware that his/her behavior may be inappropriate or risky.
• A person may be more likely to engage in risky behavior, including drinking and driving, sexual activity (like unprotected sex) and aggressive or violent behavior.
• A person is less likely to recognize potential danger.

Long-Term Consequences as the Teen Brain Develops:

• Research shows that drinking during the teen years could interfere with normal brain development and change the brain in ways that:
  • Have negative effects on information processing and learning.
  • Increase the risk of developing an alcohol use disorder later in life.

People who drink are affected even before they show signs of being drunk, especially when it comes to decision-making abilities.

At first, alcohol causes people to feel upbeat and excited. But this is temporary and they shouldn’t be fooled.

If drinking continues, the effects on the body—and the potential risks—multiply. Here’s what can happen:

• Inhibitions and memory: People may say and do things that they will regret later, or possibly not remember at all. Inhibitions are lost – leading to poor decision making.
• Decision-making skills: When they drink, individuals are more likely to be impulsive. They may be at greater risk for having an alcohol-related traffic crash, getting into fights, or making unwise decisions about sex.
• Coordination and physical control: When drinking leads to loss of balance, slurred speech, and blurred vision, even normal activities can become more dangerous.
• Death: Drinking too much alcohol can also lead to death. If people drink too much, they will eventually get sleepy and pass out. Reflexes like gagging and breathing can be suppressed. That means they could vomit and choke, or stop breathing completely.

And finally, it’s easy to misjudge how long alcohol’s effects last. Alcohol continues to affect the brain and body long after the last drink has been finished. Even after someone stops drinking, alcohol in the stomach and intestine continues to enter the bloodstream, impairing judgment and coordination for hours.

Teens drink for a variety of reasons. Some teens want to experience new things. Others feel pressured into drinking by peers. And some are looking for a way to cope with stress or other problems. Unfortunately, drinking will only make any problems a person has already worse, not better.

Prescription drug misuse has become a large public health problem, because misuse can lead to addiction, and even overdose deaths. For teens, it is a growing problem:

• After marijuana and alcohol, prescription drugs are the most commonly misused substances by Americans age 14 and older.
• Teens misuse prescription drugs for a number of reasons, such as to get high, to stop pain, or because they think it will help them with school work.
• Most teens get prescription drugs they misuse from friends and relatives, sometimes without the person knowing.
• Boys and girls tend to misuse some types of prescription drugs for different reasons. For example, boys are more likely to misuse prescription stimulants to get high, while girls tend to misuse them to stay alert or to lose weight.

es, more than half of the drug overdose deaths in the United States each year are caused by prescription drug misuse. Deaths from overdoses of prescription drugs have been increasing since the early 1990s, largely due to increases in misuse of prescription opioid pain relievers. More than 29,700 people died from a prescription drug overdose in 2015, with alarming increases among young people ages 15 to 24.¹ Learn more about drug overdoses in youth.

Mixing different types of prescription drugs can be particularly dangerous. For example, benzodiazepines interact with opioids and increase the risk of overdose. Also, combining opioids (pain relievers) with alcohol can make breathing problems worse and can lead to death.

Prescription and over-the-counter drugs are the most commonly misused substances by Americans age 14 and older, after marijuana and alcohol.

Below is a chart showing the percentage of teens who misuse prescription drugs.