Using cannabis to deal with pain, anxiety, or other emotional struggles might increase the risk of paranoia, according to new research from King’s College London and the University of Bath.
In one of the largest surveys ever done on cannabis use, researchers asked over 3,000 adults why they started using cannabis and how much they now use each week.
The team found that people who began using cannabis to manage physical pain, anxiety, or depression were more likely to feel paranoid and anxious, compared to those who started out of curiosity or for fun.
This research, published in BMJ Mental Health, shows that your reasons for using cannabis may shape how it affects your mental health. People who used it to self-medicate scored higher on measures of paranoia, depression, and anxiety. Many even had scores high enough to suggest they might benefit from counseling.
The study also looked at how much cannabis people used. On average, participants consumed about 206 units of THC — the main chemical in cannabis that makes people feel high — per week.
This is roughly equal to 10–17 joints if using cannabis with 20% THC. But people who started using cannabis to cope with anxiety, depression, or because a family member used it often consumed even more — up to nearly 287 THC units weekly.
A second study by the same research team, published in Psychological Medicine, focused on childhood trauma. Over half of the people in the survey had experienced some form of trauma in childhood. Those who went through emotional or physical abuse as children were more likely to feel paranoid as adults.
Even more concerning, people with trauma — especially emotional abuse or household conflict — were likely to use more cannabis and to feel more paranoid. However, not all trauma types had the same effect. People who experienced neglect, bullying, or sexual abuse did not show the same link between trauma, cannabis use, and paranoia.
The research suggests that people with past trauma may be more vulnerable to the mental health risks of cannabis. Using cannabis to self-soothe might make things worse, not better.
Experts say this shows the need for better education around cannabis use, especially in places where it is being legalized. Professor Marta Di Forti, who helped lead the study, warns that cannabis is not always harmless. People using it to escape pain may face even more serious problems later.
These findings could change how doctors and therapists talk to patients who use cannabis. Screening for past trauma may help health professionals provide better care and help people avoid serious mental health issues.
The researchers hope these results will encourage thoughtful cannabis policies that include strong education and mental health support for people at risk.
The study is published in BMJ Mental Health.
Copyright © 2025 Knowridge Science Report. All rights reserved.
