Cannabis: the facts – Healthy body
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Cannabis (also known as marijuana, weed, pot, dope or grass) is the most widely used illegal drug in the UK.
The effects of cannabis vary from person to person:
- you may feel chilled out, relaxed and happy
- some people get the giggles or become more talkative
- hunger pangs (“the munchies”) are common
- colours may look more intense and music may sound better
- time may feel like it’s slowing down
Cannabis can have other effects too:
- if you’re not used to it, you may feel faint or sick
- it can make you sleepy and lethargic
- it can affect your memory
- it makes some people feel confused, anxious or paranoid, and some experience panic attacks and hallucinations – this is more common with stronger forms of cannabis like skunk or sinsemilla
- it interferes with your ability to drive safely
If you use cannabis regularly, it can make you demotivated and uninterested in other things going on in your life, such as education or work.
Long-term use can affect your ability to learn and concentrate.
Can you get addicted to cannabis?
Research shows that 10% of regular cannabis users become dependent on it. Your risk of getting addicted is higher if you start using it in your teens or use it every day.
As with other addictive drugs, such as cocaine and heroin, you can develop a tolerance to cannabis. This means you need more to get the same effect.
If you stop using it, you may get withdrawal symptoms, such as cravings, difficulty sleeping, mood swings, irritability and restlessness.
If you smoke cannabis with tobacco, you’re likely to get addicted to nicotine and risk getting tobacco-related diseases such as cancer and coronary heart disease.
If you cut down or give up, you will experience withdrawal from nicotine as well as cannabis.
Cannabis and mental health
Regular cannabis use increases your risk of developing a psychotic illness, such as schizophrenia. A psychotic illness is one where you have hallucinations (seeing things that are not really there) and delusions (believing things that are not really true).
Your risk of developing a psychotic illness is higher if:
- you start using cannabis at a young age
- you smoke stronger types, such as skunk
- you smoke it regularly
- you use it for a long time
- you smoke cannabis and also have other risk factors for schizophrenia, such as a family history of the illness
Cannabis also increases the risk of a relapse in people who already have schizophrenia, and it can make psychotic symptoms worse.
Other risks of cannabis
Cannabis can be harmful to your lungs
People who smoke cannabis regularly are more likely to have bronchitis (where the lining of your lungs gets irritated and inflamed).
Like tobacco smoke, cannabis smoke contains cancer-causing chemicals, but it’s not clear whether this raises your risk of cancer.
If you mix cannabis with tobacco to smoke it, you risk getting tobacco-related lung diseases, such as lung cancer and chronic obstructive pulmonary disease (COPD).
You’re more likely to be injured in a road traffic accident
If you drive while under the influence of cannabis, you’re more likely to be involved in an accident. This is one reason why drug driving, like drink driving, is illegal.
Cannabis may affect your fertility
Research in animals suggests that cannabis can interfere with sperm production in males and ovulation in females.
If you’re pregnant, cannabis may harm your unborn baby
Research suggests that using cannabis regularly during pregnancy could affect your baby’s brain development.
Regularly smoking cannabis with tobacco increases the risk of your baby being born small or premature.
Cannabis increases your risk of cardiovascular disease and stroke
If you smoke it regularly for a long time, cannabis raises your chances of developing these conditions.
Research suggests it’s the cannabis smoke that increases the risk, not the active ingredients in the plant itself.
Does my age affect my risks?
Your risk of harm from cannabis, including the risk of schizophrenia, is higher if you start using it regularly in your teens.
One reason for this is that, during the teenage years, your brain is still growing and forming its connections, and cannabis interferes with this process.
Does cannabis have medicinal benefits?
Cannabis contains active ingredients called cannabinoids. Two of these – tetrahydrocannabinol (THC) and cannabidiol (CBD) – are the active ingredients of a prescription drug called Sativex. This is used to relieve the pain of muscle spasms in multiple sclerosis.
Another cannabinoid drug, called Nabilone, is sometimes used to relieve sickness in people having chemotherapy for cancer.
Trials are under way to test cannabis-based drugs for other conditions including cancer pain, the eye disease glaucoma, appetite loss in people with HIV or AIDS, and epilepsy in children.
We will not know whether these treatments are effective until the trials have finished.
Trying to give up?
If you need support with giving up cannabis:
- see your GP
- visit Frank’s Find support page
- call Frank’s free drugs helpline on 0300 123 6600
- see Drugs: where to get help
You’ll find more information about cannabis on the Frank website.
Page last reviewed: 31 October 2017
Next review due: 31 October 2020
How cannabis (marijuana, weed, dope, pot) affects you, the risks and where to find help if you're trying to quit.
Experts Explain What Happens In Your Body If You Smoke Weed Daily, Weekly, Or Monthly
ItвЂ™s not as cut & dry as you learned in D.A.R.E.
Sometimes picking up a joint can seem like the best way to wind down (particularly if you live in a place where it’s legal) вЂ” but you might be wondering what cannabis does to your body over time. It’s a complex plant, and its impact on your health is still being studied, with decades of legal restrictions slowly lifting.
Pot has been found to have more health benefits over the last few years, like alleviating chronic pain and helping insomnia. But depending on how often you smoke, there could be risks, too.
“Work from my lab and others does suggest that frequency of use correlates positively with cannabis-related problems,” Mitchell Earleywine Ph.D., professor of psychology at the University of Albany, tells Bustle. “But the effect isn’t particularly big.” Your experience will be pretty different if you’re an occasional weed-brownie-haver as opposed to a several-times-a-day vaper.
Whether you identify as an occasional or daily user, a bong ripper, or gummy-snacker, here’s what’s happening in your body when you use weed.
Scientists are still trying to figure out how many of weed’s effects are temporary, what’s long-term, and how much dosage is required. (And then there’s the fact that men react differently to women when it comes to cannabinoids, which is often not used as a factor in studies.) “Occasional use by adults is generally safe, particularly for those who use the vaporizer,” Earleywine says.
One way a smoking session every few months may hurt your body is in immune response. There is evidence cannabinoids interferes in our resistance to infection. One study in Journal of Cannabis Research in 2020 found that heavy cannabis use вЂ” defined as seven or more hits in the past 30 days вЂ”В tended to increase white blood cells, which indicates that the immune system is under strain, but it’s not clear if occasional use will have the same effects.
A single hit will significantly impair your balance, your reaction time, and your ability to form new memories, but these effects will wear off as your high does. “The impairment from cannabis relates to impaired ability to deal with unexpected events, like avoiding a car that comes out of nowhere,” Matthew W. Johnson, Ph.D., professor of psychiatry at Johns Hopkins University School of Medicine, tells Bustle. And 2015 study in Schizophrenia Bulletin has found that just one hit can cause paranoia in some people, which you probably knew.
Determining whether risks increase with use when it comes to cannabis is a bit tricky. “Monthly use has no meaningful impact,” Jonathan Caukins Ph.D., professor of operations research and public policy at Carnegie Mellon University’s Heinz College and an expert on cannabis legalization, tells Bustle.
Having a monthly smoke may to be linked to temporary harm to cognitive skills like memory, assimilation of new information, and attention, but it’s likely to be pass pretty quickly. According to a review of studies published in Journal of Addiction Medicine in 2012, a monthly user will “spring back” from this damage over four weeks of abstinence.
One study, published in 2014 by the Society Of Prevention Research, looked at boys throughout their lives, from 7th grade to age 35. Monthly weed use was common, and it didn’t seem to make a difference to the 35-year-olds’ health issues, medications, injuries, or hospitalizations. Men who didn’t smoke weed had the same outcomes.
When you smoke weekly, health risks go up. A 2020 study of 3,400 people published in JACC Cardiovascular Imaging found that weekly users showed problems with the left ventricles of their hearts and shifts in their heart structure. Regular use has also been linked to an increased risk of heart attacks, particularly in the first few hours after a session.
A 2011 review of weekly users, published in Indian Journal of Psychiatry, found that going cold turkey for a month can restore cognitive powers, from reaction time to memory and dexterity. Other studies, though, only showed partial recovery. The Canadian Centre on Substance Abuse & Addiction did a roundup of studies in 2019 that found weekly smoking was much less likely to produce permanent cognitive problems than daily smoking.
For all the fearmongering, even daily use of weed isn’t going to be that harmful, all things considered. A 2015 study published in Annals of the American Thoracic Society stated fairly definitively that, even after 20 years of daily use, weed smokers were still able to expel the same amount of air from their lungs as non-smokers.
The scientific opinion on daily smoking and lung cancer isn’t clear either. Cancer Research UK found that some studies believe there is a link, while others don’t believe the indications are strong enough. They point out that the huge variation in the strength of weed, the fact that people sometimes smoke it with tobacco, and the different ways individuals process it all make a link hard to pin down. “Although cannabis does increase symptoms of bronchitis like coughing and wheezing, it does not appear to elevate risk for lung cancer,” Earleywine says.
There’s an argument that daily, heavy spliff use may actually alter the structure of your brain. “Daily use has many dangers, including most obviously altering brain pathways,” Caukins says. A 2014 study published in PNAS found that daily users seemed to have a smaller orbitofrontal cortex, the part of the brain that helps with emotional and decision-oriented processing, but also had denser links between different parts of the brain. A 2017 study published in Pediatric Neurology also found that chronic weed use was linked to damage in the brain’s white matter.
“One effect is subtle memory deficits,” Johnson says. “These seems to disappear with about a month of abstinence.” Daily use can also result in dependence, he says, which means you start feeling irritable, sleepless and lose your appetite whenever you stop.
The Bottom Line
“The data on cannabis and altered brain structure only seem to appear in those who used the plant heavily while still very young,” Earleywine cautions. And these findings have been hard to replicate. “Plenty of daily users have literally no problems related to the plant, and some occasional users consume in unsafe ways,” he says. “Those who begin use early in life tend to show more problems with the plant than those who start when they are older.”
So frequency may not be the be-all and end-all for determining how weed is affecting your health; what time of day you smoke, how you do it, and how young you were when you began smoking are all factors, too.
Readers should note that laws governing cannabis, hemp and CBD are evolving, as is information about the efficacy and safety of those substances. As such, the information contained in this post should not be construed as legal or medical advice. Always consult your physician prior to trying any substance or supplement.
Jonathan Caukins Ph.D.
Mitchell Earleywine Ph.D.
Matthew W. Johnson, Ph.D.
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This article was originally published on April 20, 2016
Cannabis’ impact on your health is still being studied, with decades of legal restrictions slowly lifting.