At a glance
- Motivation matters: People who first used cannabis to self-medicate for pain, anxiety, or depression showed higher paranoia and heavier use than those who started for social or recreational reasons.
- Childhood trauma increases risk: Experiences of abuse were strongly linked to later paranoia and greater cannabis consumption.
- Public health implications: Findings highlight the need for education, screening, and support as cannabis becomes more widely available.
New research from King’s College London’s Institute of Psychiatry, Psychology & Neuroscience (IoPPN), in collaboration with the University of Bath, has found that the reasons people begin using cannabis can significantly influence their risk of developing paranoia.
The findings come from Cannabis & Me, the largest survey of its kind. One study, published in BMJ Mental Health, asked more than 3,000 current and former cannabis users about their reasons for first trying the drug, their mental health, and their weekly consumption. Those who reported starting cannabis use to self-medicate physical pain, anxiety, depression, or minor psychotic symptoms had the highest paranoia scores. In contrast, those who began using cannabis for fun, curiosity, or social reasons reported the lowest levels of paranoia and anxiety.
Dr Edoardo Spinazzola, first author of the study, said,
“Our study provides vital evidence on how the reason someone first starts using cannabis can dramatically impact their long-term health. This research suggests that using cannabis as a mean to self-medicate physical or mental discomfort can have a negative impact on the levels of paranoia, anxiety, and depression.”
The survey also tracked consumption using standard THC units, the main psychoactive component of cannabis. On average, respondents consumed 206 THC units weekly, roughly 10-17 joints of common high-strength cannabis. Those who first used cannabis to cope with anxiety or depression, or because of family members’ use, consumed even more, averaging between 248 and 287 units a week.
Professor Tom Freeman, co-author and Director of the Addiction and Mental Health Group at the University of Bath, explained, “A key finding of our study is that people who first used cannabis to manage anxiety or depression, or because a family member was using it, showed higher levels of cannabis use overall. In future, standard THC units could be used in a similar way to alcohol units, for example, to help people to track their cannabis consumption and better manage its effects on their health.”
A second study, published in Psychological Medicine, examined how childhood trauma influences the relationship between cannabis use and paranoia. Just over half of participants reported some form of trauma, with physical and emotional abuse emerging as the strongest predictors of later paranoia. Those who reported sexual, emotional, or physical abuse also consumed higher amounts of THC weekly.
Dr Giulia Trotta, first author of this study, said,
“This comprehensive study is the first to explore the interplay between childhood trauma, paranoia, and cannabis use among cannabis users from the general population. We have not only established a clear association between trauma and future paranoia, but also that cannabis use can further exacerbate the effects of this, depending on what form the trauma takes.”
Professor Marta Di Forti, senior author of both studies, added, “My experience in clinic tells me that there are groups of people who start to use cannabis as a means of coping with physical and emotional pain. My research has confirmed that this is not without significant further risk to their health and wellbeing, and policy makers across the world should be mindful of the impact that legalisation, without adequate public education and health support, could have.”
Together, these studies highlight that both early motivations for cannabis use and experiences of childhood trauma can shape later risks of paranoia and heavy use, underlining the importance of public health education and early clinical screening.
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The post Cannabis, Trauma, and the Path to Paranoia first appeared on MQ Mental Health Research.
