[Skip to Content]


Medically reviewed by: Amy W. Anzilotti, MD

What Is Marijuana?

Marijuana (also called weed, dope, or pot) is a mix of dried flowers, stems, seeds, and leaves from the cannabis plant. THC (tetrahydrocannabinol) is the ingredient in marijuana that causes someone to feel high.

In the past, most people who used marijuana smoked it like a cigarette (a joint) or from different types of pipes. Now it's more common to vape it with a vape pen. Mixing it into foods or drinks (edibles) like brownies, teas, alcohol, or gummies is also very popular. Some people use a “wax pen” or “dab pen” to inhale the oil or other extracts from the cannabis plant. Called “dabbing,” this delivers high concentrations of THC.

Synthetic marijuana (“fake weed”) is made in a lab. It doesn't contain any THC from a marijuana plant, but it is marketed as having the same effects. The makers often spray the synthetic marijuana onto herbs to give the impression that it's natural, but it is not. Fake weed products are largely unregulated, so there is little information about whether they're safe. But it looks like their effects can be unpredictable and dangerous. And withdrawal from synthetic marijuana is more serious and lasts longer than withdrawal from THC products.

What Are the Effects of Marijuana?

Marijuana has both short-term and long-term effects. The effects vary from person to person and depend on how much marijuana is used. Smoking marijuana leads to effects very quickly while edibles take longer to have an effect.

Short-Term Effects

After using marijuana, someone may feel more relaxed, hungry, sleepy, and have a different sense of reality (for example, colors may seem brighter). Some people may feel anxious and distrustful of others. In rare cases, it can cause a short-term psychosis with hallucinations (seeing things that aren’t there) and paranoia (feeling very threatened). It affects the skills needed to drive safely and may lead to car crashes.

Long-Term Effects

People who use marijuana over a long period of time might:

  • Find it harder to remember, multitask, and pay attention.
  • Cough more, get more lung infections, and get lung scarring.
  • Be more likely to get depressed, be anxious, or have thoughts of suicide.
  • Become dependent on marijuana and develop cannabis use disorder. This means they can’t stop using marijuana even when it causes health, social, and school problems. Cannabis use disorder can make someone:
    • have trouble in social situations
    • have memory problems
    • struggle in school or at work

Also, marijuana doesn't only affect a person who uses it. Being around secondhand marijuana smoke and vapor can:

  • cause lung irritation and asthma flare-ups
  • make someone feel high because they contain THC

What If I Want to Quit?

People who use marijuana for a while can have withdrawal symptoms when they try to give it up. They may feel irritable, anxious, or depressed; have trouble sleeping; or not feel like eating.

Marijuana withdrawal can be a bit like caffeine withdrawal: It's usually worse a day or two after someone stops using it. After that, withdrawal symptoms gradually decrease. They're usually gone a week or two after the person no longer uses the drug.

If you want to stop using marijuana but are having trouble quitting, it can help to talk to a counselor. Studies suggest that a combination of individual counseling and group therapy sessions is the best approach for stopping marijuana use.

For more on treatment options, visit:

Medically reviewed by: Amy W. Anzilotti, MD
Date reviewed: January 2023