Your Questions About Cannabis Use, Answered
Cannabis Use: straight answers to the questions people actually ask, with the figures behind them.
The health effects and risks of marijuana, including smoked, vaped and edible products.
Key takeaways
- Cannabis use disorder: about 3 in 10 people who use marijuana have it
- Higher risk: people who start using before age 18 or use it daily
- Most useful single change: Wait for an edible to take effect before taking more.
- Commonest mistake: Driving after using cannabis.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
What is Cannabis Use?
The health effects and risks of marijuana, including smoked, vaped and edible products.
Why does it matter?
Cannabis is legal for adults in many states, but it can still cause dependence, impaired driving and harm to young people and pregnancies.
Cannabis use disorder for Cannabis Use?
About 3 in 10 people who use marijuana have it.
Higher risk for Cannabis Use?
People who start using before age 18 or use it daily.
What is the single most useful thing to do?
Wait for an edible to take effect before taking more.
What is the most common mistake?
Driving after using cannabis.
When should I see a doctor?
Call 911 if someone has chest pain, severe anxiety or confusion, trouble breathing or is unresponsive after using cannabis, or if a child is very sleepy after eating an edible. See your doctor for repeated severe vomiting linked to regular use.
More questions, answered
Is cannabis addictive?
Yes, cannabis can be addictive. Some people who use it develop cannabis use disorder, which means they keep using despite problems and find it hard to stop. The risk is higher for people who start young and those who use high-potency products often.
Is CBD the same as marijuana?
CBD is one compound found in cannabis, and it does not cause a high. One prescription CBD medicine is FDA approved for certain seizure disorders. Many CBD products sold in stores are not FDA approved, may be mislabeled and may contain THC. CBD can interact with other medicines.
What is cannabinoid hyperemesis syndrome?
Cannabinoid hyperemesis syndrome causes repeated bouts of severe nausea, vomiting and stomach pain in some people who use cannabis regularly over a long period. Many find hot showers or baths ease symptoms. The only lasting treatment is stopping cannabis. Severe vomiting can cause dehydration, so seek care.
How long after using cannabis is it safe to drive?
There is no simple answer, because the effects depend on the product, the amount and the person. Impairment can last for hours, and longer with edibles. The safest choice is not to drive at all after using, and to arrange another way home.
Can cannabis cause psychosis?
Cannabis use, especially frequent use of high-potency products, is linked to a higher risk of psychosis, including in people without a previous mental health diagnosis. The risk is higher for people with a family history of psychosis. Seek help promptly for paranoia, hallucinations or confused thinking.
Does cannabis help with sleep?
Some people feel cannabis helps them fall asleep, but regular use can change sleep quality and lead to dependence. Stopping often causes temporary sleep problems and vivid dreams. Talk with your doctor about better-tested ways to improve sleep.
Related topics
- Vaping and Teens: What the Evidence Actually Says (Teen Health)
- What the Guidance Really Says About Medicines and Driving (Medicines Safety)
- The Evidence on Diabetes and Driving, Without the Hype (Diabetes)
- What the Guidance Really Says About Supplements and the Liver (Liver Health)
Where to go next
- What People Get Wrong About Cannabis Use
- Cannabis Use for Beginners: Where to Start
- Cannabis Use — the reference entry
- Substance Use: The Complete Guide
- What the Guidance Really Says About Vaping and E-Cigarettes
- What the Guidance Really Says About Stimulant Use
When to speak to a doctor
Call 911 if someone has chest pain, severe anxiety or confusion, trouble breathing or is unresponsive after using cannabis, or if a child is very sleepy after eating an edible. See your doctor for repeated severe vomiting linked to regular use.
Where this comes from
- CDC — Cannabis and Public Health
- National Institute on Drug Abuse — Cannabis (Marijuana)
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
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