No Association Between Cannabis Use Only and Psychosis


A new study published in Drugs and Alcohol Today has found no increased risk for psychosis among individuals who use cannabis and abstain from other “drug use.”

A team of seven researchers from the UK, Ireland, and Denmark set out to explore the association between recreational drug use (cannabis only vs polydrug) and ICD-10 psychotic disorders, noting that few studies have examined the relationship between psychosis and cannabis use in combination with other illicit substances.

Researchers analyzed self-reported measures of lifetime drug use among 4,718 Danish 24-year-olds. The participants’ reports were linked to the Danish psychiatric registry system which was utilized as an objective mental health status indicator.

Research Findings

“Multivariate binary logistic regression analysis was used to examine the association between drug use (no drug use, cannabis only, cannabis and other drug) and ICD-10 psychotic disorders, while controlling for gender and parental history of psychosis. Compared with no drug use, the use of cannabis only did not increase the risk of psychosis while the odds ratio for cannabis and other drug were statistically significant.”

Given their findings, researchers proposed that the psychosis risk could be related to the use of multiple psychoactive substances in conjunction.

About Author Managing Editor, I studied Literature at UC Irvine and earned my MBA at Chapman University. Eventually, I will spend my days writing fiction from a small balcony in Maastricht, Netherlands, a couple of hours south of Amsterdam. For now, I'm quite content with a life of reading, writing, and surfing in San Clemente, CA.


  1. In the UK cannabis is usually smoked with tobacco in joints, so most cannabis consumers here are doing poly drug use just to get stoned. This might go someway to explaining the claimed association of cannabis with psychosis which has had so much press coverage here.

    • I haven’t used tobacco in a spliff for years ─ and while it made sense with hash, bud is best on its own.

      And there are few things I find more life-affirming than relaxing with a spliff of sweet, potent sativa…

      And sativa comes sans the penetrating pungency of skunk.

  2. Rob Woodside on

    The last resort of the Reefer Madness know nothings is road and workplace safety and turning teenagers into psychotics. The fact that safety issues haven’t destroyed states where it has been legalized goes unnoticed as will this anti psychotic finding.

    I never noticed any synergistic effects with tobacco and marijuana. It seemed to me that the tobacco just made it taste bad, but I was too polite to complain.

  3. I am a huge advocate of cannibus legalization and use for adult, but I have had 2 episodes of psychosis from cannibus use only. Granted, I don’t believe that I have a psychotic disorder (I haven’t had psychosis in my life besides from those 2 incidents), but there is a clear link between cannibus use and psychosis for me personally. These psychotic breaks happened after about 2 months of daily cannibus use, and they were intense, completely delusional, and lasted for weeks. There are many parts of those weeks that I have no recollection of. I’m not trying to put a bad name on cannibus, but I want people to know that my experience of cannibus-induced psychosis is real, along with a very small percentage of other people.

    • Also Evan, If your cannabis has been sourced from an illegal or unregulated supply, it might have been mold, fertilizers, or any one of a list of contaminants used to add weight or sparkle that caused your problems?
      I know some contaminants can cause breathlessness and abnormal heart rate, at the very least.
      Either way, in a safe regulated market someone could go the the pharmacy/dispensary and mention that they have had issues in a certain area like anxiety or worse, where they would get help choosing something to actually help with that, or maybe even advice to avoid it altogether, or on proper doses, THC levels and methods of consumption, rather than potentially exacerbate your issues using the current system of “Smoke any amount of whatever we happened to get our hands on and see how that goes”.

      Unfortunately, when all these nay sayers and government say no to legal cannabis because of some imagined tiny harm risk. The cannabis users don’t just stop using cannabis automatically, they continue to source any old crap available and support criminal gangs.
      The whole point is just to quickly shift those currently consuming street gang crap in any old way, to consuming safe cannabis the proper responsible way.

  4. Hmmm! Gotta say I have something of a problem with your misspelling of cannabis, Evan.
    It just seems paradoxical that *any* cannabis-user would be unable to spell its name…
    So, that is causing me to seriously doubt your truthfulness on this subject, period.
    And if you *are* lying about this, I can only feel sorry for you, as it would suggest you have a lack of the most basic intelligence.
    I’m in my 69th year and began toking in late ’74 and have rarely been without a daily smoke since that time.
    If I had ever felt that it had caused me a psychotic episode I would have quit immediately….

  5. Ditto on PJ RAFTER’s comment. I’m 64 and started smoking recreationally in ’73 in earnest. Been growing most of mine since ’98 so I haven’t been exposed to all the so called “safe” pesticides except perhaps in rare occasions when sharing someone else’s smoke. I still use recreationally but I do really replace all pharma so far for Osteoarthritis symptoms.

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