What is cannabis?

Cannabis, also known as weed, hash, marijuana, dope, grass, pot, puff, or ganja is a psychoactive drug
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Remember: All drugs, including the misuse of prescribed medication, can pose serious health risks, up to and including possible death.

Cannabis is a psychoactive drug that comes from a plant. Some people refer to cannabis as weed or marijuana, among other names. When someone is ‘stoned’ or ‘high’, it usually means they are feeling the effects of cannabis.

Cannabis can be smoked (in a pipe, a bong, or rolled with tobacco as a spliff or joint) or eaten, usually baked into cakes or added to sweets. When smoked, the effects are pretty instant; in minutes. These may last up to one hour with low doses and for two to three hours with high doses. When eaten, the effects of cannabis take longer to be felt; normally around an hour. 

What happens when you smoke weed?

The way a person reacts when they smoke weed can be different for everyone. 

Depending on whether the weed you smoke makes you feel high or stoned you will have different experiences. Feeling stone can leave you feeling relaxed and heavy, whereas feeling high can make you feel giddy. You can get cravings for food called “the munchies” and it feels like you can’t get enough food. Other people might have unpleasant reactions, including fearfulness, confusion, severe panic and anxiety, paranoid reactions, and hallucinations. 

Many people also have a heightened awareness of sound, colour and textures, or they may have a light-headed floating sensation. Things like music or TV might suddenly seem fascinating and unusually moving.

Usual doses of cannabis may also interfere with short-term memory and learning ability, as well as co-ordination (so manual skills are impaired). Moderate doses may interfere with clarity of speech. 

What are the risks of cannabis?

Like taking any drug, there are a number of risks associated with smoking weed.

Damage to throat and lungs

Like cigarettes, smoking cannabis can damage your throat and lungs. It may cause chronic bronchitis, coughing, hoarseness, and other respiratory problems similarly associated with tobacco smoking.

Mental health problems

Users may undergo temporary and in a small percentage of cases, severe psychological distress and confusion. Heavy use amongst those with a mental illness may make their condition worse.

It has also been suggested that there may be a slightly increased risk of developing schizophrenia in those who started using cannabis at a young age (under the age of 18). As with all drugs, it appears that risk increases with use, so someone who uses cannabis daily may be more likely to suffer side effects than someone who only uses it occasionally.

A lack of energy

Users may appear lack energy and perform poorly at work or education.

Fertility problems

Among the other known or suspected long term effects of continuous cannabis use are decreased sperm count and sperm mobility, interference with ovulation and pre-natal development and impaired immune system response. 


It is possible to grow dependent on cannabis. People who smoke weed regularly might find it difficult to cope without it. If you think you might be dependent on drugs, there are a number of services that can help. Find a service near you here or contact the Drugs Helpline on 1800 459 459 to find out about options in your area.

What does the law say about cannabis?

All cannabis products are controlled by the Misuse of Drugs Acts. Cannabis is included in Schedule 1, which prohibits its medical and non-medical use.

It is therefore illegal to grow, produce, supply or possess any of the drugs, except in accordance with a licence from the Minister for Health for research or analysis. It is also an offence to allow premises to be used for cultivating, supplying or smoking cannabis.

In some countries, it is legal to purchase, possess, and use cannabis. There have been attempts to decriminalise cannabis in Ireland, and there could be new legislation in the future that would make it legal to use cannabis. For now however, it is still illegal.

What to do if cannabis users experience feelings of tension and anxiety

  • Calm the person down and reassure them.
  • Talk quietly and explain these feelings will pass.
  • Keep them away from bright lights and loud noises. Encourage them to breathe deeply and slowly in order to prevent hyperventilation.

Support services

  • Drugs.ie: Online information and support for drug and alcohol use. Includes a national directory of drug and alcohol services
  • HSE Drugs, Alcohol, HIV and Sexual Health Helpline: Freephone 1800 459 459.
  • The Club Drug Clinic offers advice, support and detoxification for GHB (Liquid Ecstasy, G) and other chemsex and club drugs is an integrated person centred specialist addiction service: Tel 016488600
  • Rialto Community Drug Team
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