Cannabis
Cannabis is the most commonly used illegal drug among young people in the UK. While some view it as relatively harmless, cannabis use during adolescence can have significant effects on mental health, brain development, motivation, and emotional wellbeing.
Professionals working with children and young people play a key role in spotting the signs of cannabis use, understanding the associated risks, and having non-judgemental, informed conversations that promote safety and informed choices.
Use can range from occasional, low-risk experimentation to regular or dependent use that impacts education, relationships, health and safety. Identifying early signs and offering timely support can reduce long-term harm and help young people build healthier coping strategies.
-
Cannabis can be used in a variety of ways, and its effects vary depending on how it is taken, how much is used, and the individual’s physical and mental health. It is difficult to measure how strong a dose is, especially with unregulated products. For professionals, it’s important to understand these methods to recognise signs of use and provide accurate, non-judgemental advice.
Smoking (Spliffs or Joints)
In the UK, cannabis is often rolled into a cigarette, commonly referred to as a spliff or joint. Some people mix it with tobacco, while others use cannabis alone.
Onset: 1 to 2 minutes
Duration: 40 minutes to 1 hour
Common effects: Feeling 'stoned', giggly, relaxed, sleepy, confused or paranoid
Possible risks: Nausea, hallucinations, anxiety or panic
Health note: Mixing cannabis with tobacco increases the risk of nicotine addiction and tobacco-related illnesses. For more information, see our [Smoking category].
Smoking (Bongs or Pipes)
Cannabis may also be smoked using a bong or pipe. These devices often involve mixing cannabis with tobacco and inhaling the smoke through water.
Onset: 1 to 2 minutes
Duration: 40 minutes to 1 hour
Common effects: Similar to spliffs — users may feel relaxed, giggly, tired, or disoriented
Possible risks: As above, with added risk from inhaling smoke deeply and rapidly
Edibles (Food and Drink)
Cannabis can be mixed into food or drink — known as edibles. These are increasingly common in the form of sweets, cakes or drinks. Dosing is unpredictable, and effects can be much stronger or longer-lasting than with smoking or vaping.
Onset: Up to or over 1 hour
Duration: Several hours, sometimes lasting into the next day
Common effects: Strong intoxication, confusion, paranoia, laughter, extreme tiredness
Possible risks: Accidental overconsumption, nausea, hallucinations, anxiety
Vaping
Vaping cannabis involves heating it using a vaporiser instead of burning it. This has become more popular, especially among young people.
Onset: 1 to 2 minutes
Duration: 40 minutes to 1 hour
Common effects: Similar to smoking — may feel relaxed, drowsy, giggly, or paranoid
Risks and concerns: Little is known about the long-term health impacts of vaping cannabis.
Detection challenge: Cannabis vapes often produce little to no smell, making them harder for parents, carers and professionals to detect
-
Cannabis use can affect young people differently to adults. Because their brains and bodies are still developing, they may be more vulnerable to both short- and long-term health risks. While some young people may view cannabis as harmless, regular use can have serious consequences for their physical, emotional and cognitive wellbeing.
Short-Term Effects
Cannabis affects everyone differently, but common short-term effects in young people include:
Changes in mood – feeling relaxed, giggly or calm, but also anxious, paranoid or low
Impaired memory and concentration – difficulty focusing or remembering information
Reduced coordination and reaction times – which can increase the risk of accidents or injuries
Increased heart rate – which may feel uncomfortable and cause panic in some users
Distorted perception – including altered sense of time, hallucinations or confusion
Nausea and vomiting – particularly with high doses or edibles
These effects can lead to risky decisions, poor judgement, or difficulty in school or social situations.
Long-Term Risks
Frequent or heavy cannabis use during adolescence can contribute to more serious and lasting health concerns:
Mental health issues – including anxiety, depression and, in some cases, triggering or worsening psychosis (especially in those with a family history or genetic vulnerability)
Dependence and withdrawal – some young people may become dependent on cannabis and struggle to stop using without support
Impact on motivation and achievement – cannabis use has been linked with a loss of interest in school, hobbies and future planning
Memory and learning difficulties – long-term use can affect attention span, processing speed and memory, particularly during key developmental stages
Respiratory problems – smoking cannabis (especially with tobacco) can cause chronic cough, wheezing and other lung issues
Social and Legal Consequences
In addition to health effects, cannabis use can also affect relationships, school attendance and engagement, and in some cases lead to legal issues. Young people may be unaware of how cannabis possession or supply can impact their future.
-
Conversations about cannabis can be challenging, but they are also an opportunity to build trust, share accurate information, and encourage young people to think critically about their choices. Whether you suspect use or the young person raises it themselves, how you approach the conversation matters.
1. Be Calm and Non-Judgemental
Start from a place of curiosity, not confrontation. If a young person feels judged or criticised, they are less likely to open up. Instead, use calm, open-ended questions such as:
“What do you know about cannabis?”
“Have you ever been around people who use it?”
“How do you feel about it?”
2. Create a Safe Space
Let them know the conversation is confidential (within safeguarding limits) and that you’re there to support, not punish. Keep your body language open and reassuring.
3. Focus on Understanding, Not Lecturing
Avoid scare tactics. Young people are more receptive when they feel respected and listened to. Ask what they’ve heard about cannabis, where their information is coming from, and what their views are.
4. Talk About Effects Honestly
Share balanced, age-appropriate information about the effects and risks of cannabis — especially how it can impact brain development, mental health, concentration and motivation. Be clear that while not everyone experiences harm, the risks are higher for young people.
5. Explore Reasons for Use
If they are using cannabis, try to understand the reasons behind it. Are they using it to manage stress, anxiety, peer pressure, boredom, or something else? This can help identify more appropriate ways of coping or support.
6. Encourage Reflection
Ask questions that promote self-awareness, such as:
“How does it make you feel afterwards?”
“Have you noticed any changes in your mood, memory, or energy?”
“Is there anything you’d like to change?”
7. Offer Support Without Pressure
Let them know you’re there if they need help — now or in the future. Offer information about local services or support networks, and reassure them that asking for help is a strength, not a weakness.
8. Don’t Expect One Conversation to Do It All
These conversations are often more effective over time. Keep the door open for future discussions, and check in again — even briefly — to show you haven’t forgotten or judged them.
Key message:
The goal is not to scare or shame young people, but to build trust, open up thinking, and help them make informed, safer choices — or seek support if needed.
Risk Indicators
Understanding risk indicators related to cannabis use is essential for professionals supporting children and young people. This tool uses a simple RAG (Red, Amber, Green) system to help assess levels of concern based on behaviour, frequency of use, and impact on wellbeing.
Low Risk
These indicators suggest occasional or experimental cannabis use, with no significant impact on the young person's health, behaviour, or daily functioning. The young person appears to be coping well and shows awareness of the risks.
Increased Risk
These signs suggest increasing or more regular cannabis use, with emerging concerns about its impact on wellbeing, behaviour or functioning. This level may require early intervention, support, and closer monitoring.
High Risk
These indicators reflect serious concern. Cannabis use is having a significant impact on the young person’s health, safety or ability to function. Immediate support and possible referral to specialist services may be needed.
-
These indicators suggest that the young person is aware of the risks associated with cannabis and is either choosing not to use it or is using in a low-risk, informed way. They are engaged, thoughtful, and take steps to protect their wellbeing and that of others.
The young person is aware of the risks linked to cannabis and actively takes steps to stay safe
They can confidently say no to peers and handle peer pressure in a positive way
They are part of a peer group where cannabis is used, but they choose not to use it themselves
They are able to identify potential risks related to drug use and understand how to minimise harm
They know how to respond in an emergency and are confident in seeking help if needed
They ensure they are not alone if they ever choose to use substances, prioritising safety
They take an active role in promoting safe behaviour within their friendship group
They maintain a supportive and stable peer network that respects their choices
They demonstrate responsible attitudes and behaviours around substance use
They are engaged in education, activities, and have future goals that are not impacted by substance use
-
These indicators suggest that the young person is using cannabis in ways that may begin to impact their wellbeing, safety, or decision-making. They may be experimenting regularly, showing signs of emotional vulnerability, or not consistently applying risk-reduction strategies. Early intervention, support and ongoing monitoring may be needed.
The young person is using cannabis regularly in social settings (e.g. with friends on weekends)
They are actively seeking opportunities to use cannabis but are not yet reliant on it
They have a disability or health condition that may be affected by cannabis use
They are prescribed medication and may not fully understand how cannabis could interact with it
They are aware of the risks of cannabis but lack confidence in applying safer choices
They know how to respond in an emergency, but express doubt about doing so under pressure
They use cannabis in unsafe environments, such as parks, beaches or isolated areas
They are mixing cannabis with alcohol or other substances
They are unsure whether they could resist peer pressure to use cannabis
They have a safety plan in place, but report not always following it
They describe frequent cannabis use, including episodes of overuse (e.g. using until feeling sick or unwell)
They are struggling with their mental health, which may influence or be influenced by cannabis use
They show signs of low self-esteem or low confidence that may increase their vulnerability
-
These indicators suggest the young person is at serious risk due to their substance use, associated behaviours, or underlying vulnerabilities. Cannabis or other drug use is having a significant and potentially harmful impact on their physical and mental health, safety, or functioning. Immediate action and referral to safeguarding and specialist services may be required.
The young person is using large quantities of substances or using daily
They are actively and frequently seeking opportunities to use substances
They are using substances alone or in unsafe, isolated environments
They are stealing money or possessions to fund their substance use
They are knowingly ignoring risks and taking no steps to keep themselves safe
They are engaging in criminal activity related to or driven by substance use
They are using substances in the context of sexual activity or exploitation
They are associating with unfamiliar or high-risk individuals when using substances
They describe excessive use, including blackouts, vomiting, memory loss, or using to the point of physical harm
Substance use is directly linked to their attempts to manage emotional distress, trauma or mental illness
They have a history of poor mental health and are showing signs of significant distress (e.g. high anxiety, paranoia, low mood, hallucinations)
They are self-harming without understanding the risk, or making no effort to reduce harm
They have expressed suicidal thoughts and have a plan or intent to act
They are showing a marked and sudden change in behaviour (e.g. increased aggression, extreme withdrawal, erratic mood swings)
They have significantly declined in personal hygiene, appearance or daily routines
They are putting themselves or others in clearly dangerous situations with high risk of harm
They have very low self-esteem or confidence, increasing their vulnerability
They are not attending school, college or training
They disclose experiencing or witnessing violence at home (towards themselves or others)
They are vulnerable due to disability, mental health issues, age, gender identity, or peer group influences
They show limited or no understanding of consent and healthy relationships
They are known or suspected to be at risk of child sexual exploitation (CSE) or child criminal exploitation (CCE)
Their needs are complex and may include multiple overlapping vulnerabilities