The Link Between Cannabis and Psychosis
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Cannabis is one of the most widely used substances in the world, but in recent years, experts have raised concerns about its mental health effects, especially psychosis. Psychosis is a condition where a person loses touch with reality, often experiencing hallucinations or delusions. While not everyone who uses cannabis will develop psychosis, research shows that certain patterns of use can increase the risk. This article explains what we know and offers practical advice for safer choices.
Cannabis Is Getting Stronger
One key change in cannabis over the past two decades is its potency. The main psychoactive chemical in cannabis, tetrahydrocannabinol (THC), has risen sharply in concentration. In the early 2000s, dried cannabis often contained about 4% THC. By 2023, most legal products in Canada had over 20% THC. This means that today’s cannabis is much stronger, and higher potency is linked with a greater risk of mental health problems.
High-Potency and Frequent Use Increase Risk
Studies suggest that using high-THC cannabis regularly can raise the chances of developing psychosis. Products with more than 10% THC carry a particularly high risk. The risk is even greater for people who start using at a young age, use cannabis daily, or are male. A history of mental health conditions like depression, bipolar disorder, or anxiety also increases vulnerability. While more than half of cannabis-related psychosis cases resolve within 24 hours, some people experience symptoms for a week or longer, often requiring hospitalization.
Cannabis-Induced Psychosis Can Lead to Schizophrenia
The connection between cannabis-induced psychosis and long-term mental illness is worrying. A large study in Ontario found that people who went to the emergency department for cannabis use were over 14 times more likely to develop schizophrenia-spectrum disorders within three years than the general population. For those who had cannabis-induced psychosis, the risk was more than 240 times higher. This highlights the importance of early recognition and intervention.
Treatment Focuses on Stopping Use and Managing Symptoms
If someone develops psychosis linked to cannabis, the most important step is to stop using it. Continuing cannabis use after a first psychotic episode increases the risk of relapse. In severe cases, doctors may prescribe antipsychotic medications to reduce symptoms. Once a person’s condition improves, medication can sometimes be reduced or stopped under medical supervision.
Behavioural Support Can Help People Quit
Quitting cannabis can be challenging, especially for those who use it regularly. Behavioural therapies can help. Motivational interviewing, a counselling approach that boosts readiness to change, can improve treatment engagement. Cognitive behavioural therapy (CBT) can teach coping skills to manage cravings and reduce use. These approaches have been shown to lower psychiatric symptoms and improve daily functioning.
Key Takeaways for Safer Choices
Not everyone who uses cannabis will experience psychosis, but the risks increase with higher potency, frequent use, and personal or family history of mental illness. Being aware of these factors can help people make more informed choices. If you or someone you know shows signs of psychosis, such as confusion, hallucinations, or extreme paranoia, seeking medical help quickly can make a big difference in recovery.