Cannabis comes from a plant. It can make you feel relaxed, giggly, anxious or paranoid.
Cannabis can come as:
- weed or grass - dried leaves and flowers (buds)
- hash - brown dried resin
- oils or concentrates
People may smoke, eat, drink or vape cannabis.
The effects of cannabis vary by what type you use and from person to person.
Cannabis is the most used illegal drug in Ireland. Young people and people with mental health difficulties are most at risk of negative effects from cannabis.
Drug category: cannabinoid
Cannabinoids are drugs or chemicals:
- from the cannabis plant
- made to mimic the effects of cannabis (synthetic cannabinoids)
They can make you feel relaxed, happy, paranoid or confused.
Other names for cannabis
Other names include: Afghan, bhang, blow, blunts, bud, bush, dab, dope, draw, ganja, grass, hash, hashish, herb, marijuana, moroccan, pollen, pot, puff, resin, sensi, shatter, sinsemilla, skunk, smoke, soapbar, spliff, squidgy black, THC, weed
Effects of cannabis
The effects of cannabis can vary depending on:
- your size, weight and sex
- if you have any health conditions or mental health difficulties
- how you take the drug
- the strength of the drug
- how much you take
- if you take alcohol, medicines or other drugs at the same time
- where you take the drug and how you feel before you take it
- if you have taken the drug before and how often
- the type of cannabis
If you smoke, dab or vape cannabis, the effects start almost immediately and can last a number of hours.
If you eat cannabis edibles, the effects can take up to 90 minutes to start and can last for some time.
How you may feel or behave
You may feel:
- relaxed or calm
- happy or giddy
- talkative
- tired or withdrawn
- confused, anxious or paranoid
- low or unmotivated
- depressed
Effects on your brain and body
Cannabis can cause:
- bloodshot eyes
- dry mouth
- increased appetite (the munchies)
- dizziness, nausea and vomiting (a whitey or white-out)
- problems with thinking or memory
- slow reaction times
- sleep problems
- increased heart rate
- fertility problems - it reduces sperm count in males and disrupts ovulation in females
- breathing problems - especially if you mix cannabis with tobacco or use plastic bottles as bongs
- paranoia
Cannabis and the developing brain
The brain continues to develop until around age 25. This means that young people are more sensitive to damage from cannabis.
Young people who start using cannabis before age 18 are more likely to have long-term problems.
These include:
- cannabis dependency
- mental health difficulties such as anxiety or depression
- problems with thinking, memory and concentration
Even low use of cannabis can affect brain health in young people.
Some people may have other risk factors that increase the risk of psychosis.
Cannabis and mental health
Cannabis can cause mental health difficulties or make existing difficulties worse. The effects on your mental health can last after other effects of the drug have stopped.
The risk is higher if you:
- have a family history of mental health difficulties
- start using cannabis at a young age
- use cannabis often
- use types of cannabis with high levels of delta-9-tetrahydrocannabinol (THC)
Mental health difficulties linked with cannabis use include:
- anxiety
- depression
- thoughts of suicide
- hallucinations - when you see, feel or hear things that are not there
- psychosis - you have confused thoughts, feelings and behaviour and you do not know what is real or not real
- schizophrenia
Cannabis is not a treatment for mental health difficulties. There are other treatments that we know are safe and effective.
Cannabis and dependency
Regular use of cannabis can cause:
- tolerance - when you need to take more of the drug to get the same effects
- dependency
Signs of dependency can include:
- cravings for a drug
- withdrawal symptoms
- continuing to use a drug even when it causes you harm
The risk is higher if you use types of cannabis with high levels of THC.
Withdrawal symptoms
If you stop taking cannabis after regular use, you may get withdrawal symptoms.
These include:
- mood swings and irritability
- anxiety
- sleep problems
- low appetite
How long does cannabis stay in your system?
It can be hard to know how long cannabis stays in your system.
There are tests to detect cannabis. But different types of tests have different detection times.
Things that affect how long a drug stays in your system
The time it takes for a drug to leave your system depends on many things.
For example:
- how much you took
- how often you take the drug
- how strong the drug was
- your age, sex and metabolism
- your general health
Medical cannabis access programme
In Ireland, people can access cannabis for medical use in limited situations.
These are when a person has:
- an eligible condition that did not respond to standard treatments
- a prescription for cannabis treatment from their medical consultant
The eligible conditions are:
- stiffness and muscle spasms (spasticity) associated with multiple sclerosis
- severe and uncontrollable (intractable) nausea and vomiting associated with chemotherapy
- severe, refractory (treatment-resistant) epilepsy
Cannabis may reduce the severity of symptoms in these conditions.
There is not enough evidence for medical use of cannabis for other conditions.