Cannabis and mental health

for children and young people

This information looks at what cannabis is, how it can affect your mental health and how to get help and support.

It’s normal to want to know about drugs. You might want to find out more about them because people around you are taking them, you might want to take them yourself, or you might just be interested to know how they feel.


This is information, not advice. Please read our disclaimer.

The cannabis plant is a member of the nettle family that has grown wild throughout the world for centuries. People have used it for lots of reasons, including to relax.

It comes in two main forms:

  • resin, which is a brown-black lump also known as bhang, ganja or hashish
  • herbal cannabis, which is made up of the dried leaves and flowering tops, and is known as weed, grass, marijuana, spliff etc.

Different kinds of cannabis have different strengths. Skunk cannabis is made from a cannabis plant that has more active chemicals in it (THC), and it can have a stronger effect on your brain.

However, cannabis varies a lot in strength, so you will not be able to tell exactly how it will make you feel until you have taken it.

Cannabis is classified under the Misuse of Drugs Act 1971 as a Class B drug. This means that if you are found with cannabis, you could get up to 5 years in prison. If you are found to be producing it and giving it to other people, you could get up to 14 years in prison. In both cases you could also receive an unlimited fine.

Cannabis is different to other Class B drugs in that police can choose to give you a warning if:

  • you only have a small amount of cannabis
  • it is for your own personal use
  • it’s the first time you’ve been caught and you don’t have a criminal record
  • you cooperate with the police.

If you’re caught with cannabis and it is your second offence, you might be given an £80 fine. If it is your third offence, you will be arrested and taken to a police station.

Since November 2018, specialist doctors have been able to prescribe cannabis-based medicines if it is felt their patients could benefit from them. However, this resource is focused on cannabis for recreational use.

There is some debate about whether cannabis should be legalised in the UK, like it has been in Canada and some US states.

When you smoke cannabis, the active compounds reach your brain quickly through your bloodstream. They then stick to a receptor in your brain that causes your nerve cells to release different chemicals. This causes you to experience different effects, which can be enjoyable or unpleasant.

Often the bad effects take longer to appear than the good ones.

  • Good effects – Feeling relaxed and talkative, and colours or music may seem more intense.
  • Bad effects – Feeling sick, panicky or paranoid, hearing voices, feeling depressed and unmotivated.

Most people who try cannabis don’t go on to use it more than a handful of times. Unfortunately, some people can find cannabis addictive and so have trouble stopping using it even when they feel like it’s having a negative effect on their lives.

There is lots of different research into the affects that cannabis can have on mental health.

Some research has shown that young people who use cannabis have an increased risk of psychosis. How strong the cannabis is you use, and how often you use it, can increase the risk of developing psychosis.

Using cannabis can also increase the risk of other mental health problems like depression and suicidal feelings.

Research suggests that people who are already at risk of developing mental health problems might be at an increased risk of showing symptoms if they use cannabis regularly. There is also evidence that if you already have a mental health problem cannabis can, in some cases, make these problems worse.

The younger you are when you start using cannabis, the more at risk of these problems you are. This is because your brain is still developing and can be more easily damaged by the chemicals in cannabis.

Stopping using cannabis can help reduce symptoms of mental health problems such as depression and psychosis. However, some people may need additional support for their mental health problems and help to stop using cannabis safely.

Synthetic cannabinoids are chemicals designed to have similar effects to cannabis. However, they are often a lot stronger and more likely to cause mental and physical illness.

Research has shown that synthetic cannabinoids are associated with delirium (feeling confused or unaware of where you are), agitation, hallucinations, violence and self-harm.

In the past, synthetic cannabinoids were legal and known as ‘legal highs’. This is one of the reasons that people sometimes think they are safer than cannabis. However, many synthetic cannabinoids are now illegal, and in many cases they can be more dangerous than cannabis.

As well as being illegal and having potential impacts on your mental health, cannabis can affect other areas of your life.

Smoking cannabis can affect your physical health, causing you to feel out of breath or giving you a cough. If you have asthma, smoking cannabis can make this worse.

If you are using cannabis often you might find that it impacts your school or home life, or means you don’t do activities that you used to enjoy. If you use a lot of cannabis it might start to cost you a lot of money.

If you feel like cannabis is having a negative impact on your physical health, mental health or social life, there are ways to get help.

There are lots of people who can help you decide whether you do have a problem, and support you with getting help. However, if you don’t talk about it, you are unlikely to get help. Mental health problems generally do get better if you treat them quickly.

Talk to someone you trust, like a friend, family member or carer. If you need to speak to a professional, they might be able to support you to have that conversation. Other people that might be able to support you are:

  • your doctor or nurse
  • teacher or school/college counsellor
  • youth worker
  • social worker

If you don’t feel comfortable speaking to someone you know, or talking to someone face-to-face, the drug advisory service FRANK has a confidential helpline open 24/7.

While you are working towards stopping using cannabis, or finding a support service, there are some things you can do to help yourself. These include:

  • Set limits – if you find you are using cannabis all the time and find it difficult to imagine stopping completely, set limits on when and how much you use instead.
  • Avoiding bulk buying – avoid buying cannabis when you have just been paid or given money to avoid buying large amounts.
  • Avoid people, places and activities that you associate with cannabis use – be aware if you are going to go into an environment where you will be more likely to use cannabis or you will be spending time with people who use it.
  • Don’t use it if you are feeling sad or depressed – while this can be difficult, it can make you feel worse or mean that you get used to using cannabis when you’re depressed.
  • Reward yourself – give yourself treats for not using cannabis, like buying food you really like or going to the cinema.

Here are some useful resources that can tell you more about cannabis and how to get support with stopping.

  • Know cannabis – A website that can help you assess your cannabis use, its impact on your life and how to make changes if you want to.
  • FRANK – Free confidential drugs information and advice.
    Helpline: 0300 123 6600
    Text: 82111
  • YoungMinds – Charity committed to improving the mental health of all children and young people.

Further reading

Cannabis and you, workbook and self help tools – this PDF booklet from Drugs and Alcohol Northern Ireland can help you develop a plan for stopping or cutting down on cannabis use, and includes lots of useful information about cannabis.

This information was produced by the Royal College of Psychiatrists’ Child and Family Public Engagement Editorial Board (CAFPEB). It reflects the best available evidence at the time of writing.

Expert authors: Dr Adam Winstock, Dr Virginia Davies, Dr Vasu Balaguru

Full references for this resource are available on request.

Published: Aug 2022

Review due: Aug 2025

© Royal College of Psychiatrists