Cannabis: the facts – Healthy body
- Food for strong bones
- Keep your bones strong over 65
- Are you at risk of falling?
- Foot problems and the podiatrist
- Looking after your feet with diabetes
- How to stop smelly feet
- Lower your cholesterol
- Keeping your kidneys healthy
- Top 10 healthy heart tips
- Common skin conditions
- Keloid scars
- Dangers of black henna
- How to sit correctly
- Posture tips for laptop users
- How to prevent germs from spreading
- How to wash your hands
- Is my child too ill for school?
- Stages of puberty
- Getting medical care as a student
- Breast changes in older women
- Tips to prevent RSI
- Safe lifting tips
- Drug addiction: getting help
- Hearing aids
- 5 ways to prevent hearing loss
- Look after your eyes
- Eye health tips for older people
- Laser eye surgery
- Contact lens safety
- Take care of your teeth and gums
- Children’s teeth
- Sweets, fizzy drinks and bottles
- Lifestyle tips for healthy teeth
- How to keep your teeth clean
- Dental check-ups
- Fear of the dentist
- Dental treatments
- Braces and orthodontics
- Teeth facts and figures
- The health risks of gum disease
- Teeth whitening
- Sunscreen and sun safety
- How to get vitamin D from sunlight
- Heatwave: how to cope in hot weather
- Out-of-hours medicines
- Your medicine cabinet
- How to use self-test kits safely
- Avoid medicines scams
- Bodybuilding and sports supplements
- How to get NHS help for your pain
- Which painkiller?
- Ways to manage chronic pain
- 10 ways to reduce pain
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.
Smoking marijuana may cause early puberty and stunts growth in boys
Boys who smoke marijuana go through puberty earlier but grow more slowly than those who have never smoked the drug according to a study presented today at the European Congress of Endocrinology in Dublin, Ireland. The findings will lead to a better understanding of the dangers of drug abuse on growth and development of children.
Scientists at the Pir Mehr Ali Shah Agriculture University Rawalpindi in Pakistan studied the levels of certain hormones involved in growth and puberty in the blood of 220 non-smoking and 217 marijuana-addicted boys. Levels of puberty-related hormones such as testosterone and luteinising hormone (LH) were increased in the marijuana smokers. In contrast, growth hormone levels were decreased in this group. It was also found that non-smoking boys were on average 4 kg heavier and 4.6 inches taller by the age of 20 than the marijuana smokers.
The research team, led by Dr. Syed Shakeel Raza Rizvi, also looked at the effect of smoking marijuana on levels of the stress hormone, cortisol, in 10 marijuana addicts; they found that marijuana smokers have significantly higher levels of cortisol than non-smokers. Dr Rizvi hypothesises that, ―marijuana use may provoke a stress response that stimulates onset of puberty but suppresses growth rate.
Marijuana is the most widely available illicit drug in Europe, it is estimated that it has been used by 80.5 million Europeans at least once in their life. The latest report from the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) reveals that the highest prevalence of marijuana use is in 15 — 24 year olds and is significantly higher among males than females. Previous studies have looked at the effect of smoking marijuana in adult rats and humans but this is the first time that the effects have been looked at in pubertal boys.
The research may have a wider impact than just health. ―Early puberty is associated with younger age of onset of drinking and smoking, and early matures have higher levels of substance abuse because they enter the risk period at an early level of emotional maturity,‖ explained Dr. Rizvi.
Boys who smoke marijuana go through puberty earlier but grow more slowly than those who have never smoked the drug according to a new study.