Cannabis can cause short-term problems such as impaired memory, attention, and coordination, anxiety or paranoia, dry mouth, red eyes, and a faster heart rate, along with long-term risks that include cannabis use disorder, bronchitis from smoking, and a higher chance of psychosis in vulnerable people. Risk grows with higher THC doses, more frequent use, and starting at a young age. Many effects ease after a person stops or cuts back, but some, particularly in adolescents, can linger.
What are the short-term negative effects of cannabis?
Most immediate effects appear within minutes of smoking or vaping and within 30 to 60 minutes of edibles, where they can last several hours. Common complaints include slowed reaction time, trouble recalling recent events, and a sense of unease that can tip into panic in sensitive users.
- Impaired short-term memory and focus
- Slowed reflexes and poor coordination
- Anxiety, paranoia, or panic, especially with high-THC products
- Increased heart rate and blood pressure
- Dry mouth, red eyes, and increased appetite
- Nausea, dizziness, or fainting
Can cannabis cause anxiety or paranoia?
Yes. THC can trigger acute anxiety, racing thoughts, and paranoid thinking, and these reactions are more common with concentrates, edibles, and in people with a personal or family history of anxiety or psychosis. CBD may soften some of these effects, but it does not remove the risk.
Can cannabis cause vomiting?
Heavy, long-term use can lead to cannabinoid hyperemesis syndrome, which causes repeated episodes of severe nausea and vomiting along with abdominal pain. Hot showers or baths often bring temporary relief, and symptoms usually stop after sustained abstinence.
what are the negative effects of cannabis
What are the long-term negative effects of cannabis?
Regular use over months or years is linked to dependence, respiratory irritation, memory problems, and worsening mental health symptoms. The earlier someone starts and the more they use, the stronger these associations tend to be.
Can cannabis be addictive?
Yes. Research suggests roughly 3 in 10 people who use cannabis develop cannabis use disorder, and the rate is higher for those who start in their teens. Withdrawal can bring irritability, insomnia, appetite changes, cravings, and restlessness.
Does smoking cannabis harm the lungs?
Smoking cannabis exposes the airways to tar and irritants that can cause chronic cough, wheezing, and bronchitis. Vaping carries its own concerns, and vitamin E acetate in unregulated cartridges has been tied to serious lung injury.
How does cannabis affect the teenage brain?
The adolescent brain is still developing, and frequent cannabis use during this window is linked to lasting problems with attention, memory, and learning. Earlier and heavier use is also tied to a greater chance of developing cannabis use disorder later.
Is cannabis linked to psychosis?
High-THC cannabis is associated with a raised risk of psychotic symptoms and, in genetically vulnerable people, schizophrenia spectrum disorders. Risk climbs with daily use and with products that contain very high THC concentrations.
Does cannabis use during pregnancy carry risks?
Cannabis use in pregnancy is linked to lower birth weight and possible effects on brain development. Major health agencies advise avoiding cannabis while pregnant or breastfeeding.
What other risks should users know about?
- Driving: Cannabis slows reaction time and judgment, and mixing it with alcohol makes impairment worse.
- Drug interactions: Cannabis can change how the body processes blood thinners, some seizure medicines, and other prescription drugs.
- Heart health: A fast heart rate can raise the chance of chest pain or, rarely, heart problems in people with existing cardiac conditions.
- High-THC products: Dabs, concentrates, and strong edibles raise the odds of acute anxiety and overconsumption.
How can you lower the risk?
Start with a low dose, especially with edibles, and wait at least two hours before taking more. Choose lower-THC products, avoid daily use, and skip cannabis entirely if you are pregnant, under 25, or have a personal or family history of psychosis.
Talk with a clinician if use is affecting sleep, work, mood, or relationships. Legally purchased, tested products from a licensed dispensary reduce exposure to contaminants, but they do not eliminate the health risks described above.