When cannabis psychosis occurs, it leads to various symptoms where a person loses contact with reality. The most frequent signs include intense paranoia and mistrust of others, combined with hallucinations and delusions of grandiosity. Their thought processes and emotions typically become muddled and chaotic, making it hard for others to understand them. These distressing symptoms usually fade considerably once marijuana use ends and appropriate medical care is received.
What is Cannabis Psychosis?
Cannabis-induced psychosis refers to a temporary loss of contact with reality that can happen after using cannabis (marijuana). Whilst serious mental health problems from cannabis are uncommon, they can occur, especially with heavy or regular use. It’s important to understand that cannabis is not the harmless substance many people believe it to be.
If you’re reading this because you’re worried about symptoms related to cannabis use, please know that you’re not alone and that help is available.
Recognising Cannabis Psychosis Symptoms
Cannabis psychosis involves experiencing symptoms that make it difficult to tell what’s real from what isn’t. These episodes are usually temporary, and with proper support and treatment, people can and do recover fully. Symptoms include:
Paranoia and suspicion: They may believe that others are plotting against you or trying to harm them.
False beliefs (delusions): The person may become convinced of things that aren’t true, even when presented with clear evidence otherwise. For example, they might believe they have special powers.
Seeing or hearing things that aren’t there (hallucinations): This might include hearing voices, seeing things others can’t see, or feeling sensations like bugs crawling on the skin when nothing is actually there.
Feeling disconnected from reality: The person may feel as though they’re watching themselves from outside their body, or that the world around them doesn’t feel real anymore.
Confused thinking: Thoughts may become jumbled and hard to follow. The person might jump between topics or struggle to speak or express themselves clearly, making conversations difficult to understand.
Aggression or hostility: – They may become unusually angry, irritable, or confrontational.
Becoming very still or unresponsive (catatonia): In severe cases, the person may become completely motionless or stop responding to others.
What Causes Cannabis-Induced Psychosis?
It’s important to remember that the development of cannabis-induced psychosis is complex. Not everyone who uses cannabis will experience cannabis-induced psychosis. It is likely that there are many factors that determine whether or not someone develops psychosis from cannabis use. These factors include other health conditions, genetics, and environmental factors.
Marijuana-induced psychosis occurs when the psychoactive compounds in cannabis – particularly high-strength THC (tetrahydrocannabinol) – disrupt normal brain chemistry. While not everyone who uses cannabis will experience these problems, certain factors significantly increase the risk, especially when they occur together.
Key Risk Factors for Cannabis Psychosis
Several factors work together to increase the likelihood of developing cannabis psychosis. The more risk factors present, the greater the chance of experiencing these serious mental health symptoms.
Strength of the Cannabis (THC Content) – Today’s cannabis is much stronger than it was in previous decades. The higher the concentration of THC, the main psychoactive ingredient, the greater the risk of developing psychosis. High-potency cannabis, sometimes called “skunk,” can contain THC levels of 20% or higher, compared to around 3-4% in cannabis from the 1990s.
Age When You Start Using – Starting cannabis use during the teenage years or early twenties significantly increases psychosis risk. This is because the brain continues developing until around age 25, and cannabis can interfere with this crucial development process. Young people’s brains are particularly vulnerable to the effects of THC.
How Often and How Long You Use Cannabis – Heavy, daily, or chronic cannabis use poses much greater risks than occasional use. People who use cannabis every day or multiple times per day are at significantly higher risk of developing psychotic symptoms than those who use it infrequently.
Existing Mental Health Conditions – Some people are naturally more susceptible to cannabis psychosis due to their genetics or existing mental health conditions. This includes those who have a family history of mental illness, particularly schizophrenia or bipolar disorder, or those who may have underlying mental health conditions that haven’t yet been diagnosed.
Existing Medical Conditions – Conditions that affect the brain, such as HIV/AIDS, Syphilis, brain tumours and neurological conditions, can put stress on the brain’s delicate chemical balance and increase vulnerability to developing cannabis psychosis.
How Cannabis Affects the Brain
Cannabis doesn’t just cause a temporary “high” – it actually changes how your brain works, particularly in systems that are essential for mental health and reality perception.
Brain Chemistry Disruption – THC interferes with important brain chemicals (neurotransmitters) including dopamine, glutamate, and GABA. These chemicals help regulate mood, perception, and thinking. When cannabis disrupts this delicate balance, it can lead to the confused thinking, false beliefs, and altered perceptions that characterise psychosis.
The Endocannabinoid System – Cannabis affects your brain’s natural endocannabinoid system, which helps regulate many important functions. When THC floods this system, it can create lasting imbalances that contribute to mental health problems, particularly with repeated use.
Marijuana as a Trigger – It’s important to understand that cannabis rarely causes psychosis entirely on its own. Instead, it often acts as a trigger that, combined with other factors like genetics, stress, or existing vulnerabilities, can push someone over the threshold into a psychotic episode. Think of it as the final piece in a puzzle… without cannabis, the psychosis might never have occurred, but cannabis alone usually isn’t the complete picture.
Important to remember: Today’s cannabis is often much stronger than it was in the past, which increases the risk of both immediate problems and longer-term mental health issues. The effects can vary greatly between individuals – some people may use cannabis with few obvious problems, whilst others may develop serious difficulties even from occasional use.
Understanding these risk factors can help you make informed decisions about cannabis use and recognise when someone might be particularly vulnerable to developing cannabis psychosis.
New Research Links Cannabis Use and Paranoia
Recent research involving over 3000 cannabis users has shown has shown that the reasons people first use cannabis can significantly affect their long-term mental health. The study found that people who initially used cannabis to self-medicate problems like pain, anxiety, depression, or unusual thoughts developed much higher levels of paranoia, anxiety, and depression, and used far more cannabis, than those who first tried it socially or out of curiosity. The research also revealed that childhood trauma, particularly emotional or physical abuse, was strongly linked to higher paranoia and heavier cannabis use, with cannabis making these problems worse. Researchers warn that self-medicating with cannabis increases the risk of addiction and psychosis, emphasising the importance of addressing underlying trauma when treating cannabis-related mental health problems.
How is Cannabis Psychosis Diagnosed?
Cannabis psychosis is a recognised medical condition that doctors can diagnose. To make this diagnosis, medical professionals look for psychotic symptoms that are clearly linked to cannabis use and that go beyond the typical effects you might expect from being “high”. Because these symptoms can be serious and sometimes frightening, people with cannabis psychosis often receive treatment in a hospital setting, particularly if they’re brought to the emergency department. This allows doctors to ensure the person is safe and to provide immediate support.
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Is Cannabis Psychosis Dangerous?
Yes, cannabis psychosis can be extremely dangerous. The psychosis itself does not cause harm, but the delusions and hallucinations experienced can convince people that they need to do dangerous things. During psychotic episodes, people may take actions that put their safety and the safety of others at risk.
For example, someone experiencing cannabis-induced psychosis might hear voices telling them they need to jump out a window. If they were to do this they could injure or even kill themselves. An episode of psychosis could convince someone that people are plotting to hurt them, and they may take measures to “defend” themselves such as hurting others.
If someone is experiencing cannabis-induced psychosis they should receive urgent medical attention.
What Should You Do If Someone You Know Has Cannabis Psychosis?
If you’re worried someone you know has cannabis-induced psychosis you should try to get them medical help.
Remember that keeping yourself safe is a priority. If you’re worried that the person is an immediate risk to themselves or others you should call 999/911 for an ambulance.
- Stop them from ingesting/smoking more cannabis
Remove the cannabis joint or edibles to stop them from taking more, and open windows to ventilate the area and clear the cannabis from the air.
- Reassure them
Listen to their concerns, and explain to them that they are safe and that you will get them help. Remember that the hallucinations and delusions they are experiencing may seem so real it may not be possible to reassure them.
- Get professional help
Contact your local medical services to get the person the appropriate help they need. Remember, if they are an immediate threat to the safety of yourself or others you should call 999.]
Cannabis Psychosis Treatment at Castle Craig
The most important thing to remember is that cannabis psychosis is usually treatable. With the right cannabis rehab programme and by stopping cannabis use, psychosis symptoms can typically improve. Recovery is possible, and many people go on to live healthy, fulfilling lives after experiencing these difficulties.
At Castle Craig we understand that one of the most difficult decisions you can face is choosing the right treatment for cannabis psychosis for yourself or someone you love. We’ve supported countless people and families who’ve come to us with the same concerns and questions. There are several key elements that make Castle Craig’s approach particularly effective.
- Thorough Assessment and Admissions Process – We provide comprehensive, in-depth assessments as part of our admissions process to ensure accurate diagnosis and determine the most appropriate level of care for each individual’s specific needs.
- Psychiatrist-Led Medical Team – Our treatment is overseen by an experienced consultant psychiatrist who specialises in drug-related mental health problems, working with a multidisciplinary team to provide expert clinical care and medication management where needed.
- Supporting the Whole Family – We actively involve family members and loved ones in the treatment process, helping them understand cannabis psychosis and providing them with the tools and knowledge to better support their loved one’s recovery journey.
- Structured Therapeutic Environment – We provide patients with appropriate structure, supervision, and support as they progress through treatment in a safe, nurturing environment that promotes personal responsibility, accountability, and meaningful connections with others.
- Building Skills for Long-term Recovery – We equip clients with practical tools, coping strategies, and ongoing support necessary to achieve greater stability and independence, giving them the confidence and resilience to live a healthy, fulfilling, and productive life free from cannabis use.
At Castle Craig, we recognise that recovery from cannabis psychosis is entirely possible, and we are committed to supporting both individuals and their families every step of the way toward lasting recovery.
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Sources
- Is there a link between marijuana use and psychiatric disorders? – National Institute on Drug Misuse
- Cannabis-Induced Psychosis: A Review – Psychiatric Times
- The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study – The Lancet
- Cannabis and psychosis: A father’s story – Rethink Mental Illness
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Khan MA, Akella S. Cannabis-induced bipolar disorder with psychotic features: a case report. Psychiatry (Edgmont). 2009 Dec;6(12):44-8. PMID: 20104292; PMCID: PMC2811144.
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Spinazzola E, Degen H, Austin-Zimmerman I, Trotta G, Chesney E, Li Z, et al. Are reasons for first using cannabis associated with subsequent cannabis consumption (standard THC units) and psychopathology?. BMJ Mental Health. 2025;28:e301810. https://doi.org/10.1136/bmjment-2025-301810
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