Risk of Schizophrenia Diagnosis Higher Following Cannabis-Induced Psychosis, Study Shows

Patients who experience substance-induced psychosis, particularly from cannabis, are at a significantly higher risk of transitioning to a diagnosis of schizophrenia.


Researchers recently published a study in the American Journal of Psychiatry exploring the transition from substance-induced psychosis to schizophrenia spectrum disorders or bipolar disorder. The data revealed that the risk of transitioning from substance-induced psychosis to a schizophrenia spectrum disorder was six times higher than that of bipolar disorder, with cannabis-induced psychosis showing the strongest association.

The authors, led by psychologist Eline Borger Rognli from the Oslo University Hospital in Norway, noted:

“Regardless of the causal explanation, it seems that some individuals who develop schizophrenia after cannabis use make this transition via cannabis-induced psychosis.”

Substance-induced psychosis, or temporary psychotic symptoms triggered by certain substances, usually subsides within a few days of halting substance use. However, in some cases, this temporary psychosis can turn into a long-term condition. In certain instances, the psychosis persists and develops into a chronic condition, with the substance serving as the initial trigger (e.g., gateway) that leads to a complete state of psychosis.

Interestingly, substance-induced psychosis is one of the unique diagnoses defined by its supposed cause or etiology – a substance. The researchers suggest that understanding the risk factors for the transition from substance-induced psychosis to schizophrenia or bipolar disorder is crucial. Such knowledge may enable earlier interventions and treatment. They comment:

“In our view, accumulated evidence raises the question of whether substance-induced psychosis would be more appropriate to consider within the schizophrenia spectrum. We have previously suggested that a continuity perspective and a stress-vulnerability model would provide a more nuanced perspective on these clinical phenomena.”

However, it is worth noting the implications of this proposed suggestion could lead to a quicker diagnosis of schizophrenia, rather than a temporary psychotic state and therefore result in the long-term use of neuroleptics.

The study included over 3,000 patients from Norway, examining factors like gender, age, number of emergency admissions due to substance-induced psychosis, and the specific type of substance that caused the psychosis.

The participants’ average age was 33, and most were male (73%). The researchers used the International Classification of Diseases (ICD-10) diagnostic criteria to diagnose substance-induced psychosis, schizophrenia, and bipolar disorder. The substances included were alcohol, opioids, cannabis, sedatives, cocaine, amphetamines, hallucinogens, and volatile solvents.

Of all the participants, 28% transitioned to a schizophrenia diagnosis, with men more likely to transition than women. A transition to a Bipolar disorder diagnosis occurred in 5% of the sample, more often in women than men. The median time for a diagnosis of schizophrenia or bipolar disorder was within one year of the initial substance-induced psychosis episode.

Regarding the types of substances, cannabis-induced psychosis had the highest transition rate to schizophrenia (36%), while alcohol-induced psychosis showed the lowest transition rate. Younger men and individuals with more emergency admissions for substance-induced psychosis had a higher risk of transitioning to schizophrenia. In contrast, the risk of transitioning to bipolar disorder was not affected by the number of emergency admissions.

In conclusion, the study suggests that substance-induced psychosis, particularly those induced by alcohol, cannabis, and multiple substances, significantly increases the risk of transitioning to schizophrenia. This finding has crucial implications for healthcare providers, who must offer tailored care and support for these individuals. The authors write:

Repeated emergency admissions may be a marker of more severe substance use, poorer mental health, or less social support. It could also be a marker of a schizophrenia development, that is, rather than a separate risk factor, it could be viewed as partly embedded in the outcome, as a transitional step toward schizophrenia.”

The authors also urge that providers consider substance-induced psychosis on the broader spectrum of schizophrenia. However, doing so may have broader and adverse implications for preventing overdiagnosis and overtreatment within psychiatric systems of care.



Rognli, E. B., Heiberg, I. H., Jacobsen, B. K., Høye, A., & Bramness, J. G. (2023). Transition from substance-induced psychosis to schizophrenia spectrum disorder or bipolar disorder. American Journal of Psychiatry, 180(6), 437–444. https://doi.org/10.1176/appi.ajp.22010076 (Link)

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Madison Natarajan, PhD candidate
Madison is a doctoral candidate in the Counseling Psychology PhD program at the University of Massachusetts Boston. She is currently completing her pre doctoral internship at the Massachusetts Mental Health Center/Harvard Medical School working in psychosis interventions across the lifespan. Madison primarily considers herself an identity researcher, assessing the ways in which dominant cultural norms shape aspects of racial and gender identity for minoritized individuals, with a specific focus on the intersection of evangelicalism and its relationship to Christian Nationalism. Madison has a family history that has been intertwined with psychiatric care, ranging from family members who were institutionalized to those practicing psychiatry, both in the US and India. Madison greatly values prioritizing the experiences of those with lived experience in her research and clinical work, and through her writing in MIA seeks to challenge the current structure of psychiatric care in the West and disseminate honest and empowering information to the community at large.


  1. “In conclusion, the study suggests that substance-induced psychosis, particularly those induced by alcohol, cannabis, and multiple substances, significantly increases the risk of transitioning to schizophrenia.”

    Why focus on cannabis in the headline when the study concluded with such a generalised outcome in that all recreational drug use (alcohol, weed, other) can result in the onset/development of psychiatric illness? Drugs affect people predisposed to mental health problems, wow, who would have known?

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      • Totally agree with you! They’re kind of beating around the bush, especially with the bizarre drugs that are used to treat schizophrenia or psychosis. A doctor also told me that when a person suddenly discontinues the strong psych meds, it damages the brain:a stroke. Trips to emergency room are mentioned in article as predictor of later schizophrenia diagnosis. But one of those trips to the emergency room are actually degrading the patients brain health? After a trip to the emergency room, mental health emergency patients are given a 7 day prescription, and in their newly drugged state, are supposed to report to a doctor to discuss further treatment. One week is not very long to get that all arranged. and so people easily go off the meds. It’s all a huge mess.

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    • “Substance induced psychosis?” From Pot? Really? “Substance induced psychosis transition from schizophrenia spectrum disorder or bipolar disorder?” Really? I mean, you got to hand it to these “researchers” their ability to concoct rhetoric to give it the veneer of scientific legitimacy. Every premise they assert is false. The logical fallacies are off the chart.

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  2. “it is worth noting the implications of this proposed suggestion could lead to a quicker diagnosis of schizophrenia, rather than a temporary psychotic state and therefore result in the long-term use of neuroleptics.” You think?

    Oh what a brilliant society we live in, let’s legalize pot. And then change the definition of “schizophrenia,” to include all people who have a bad experience with pot.

    That’s a massively slippery slope … and I will say, it’s highly unethical (and likely also illegal, since I did hear of someone who successfully sued due to just such a misdiagnosis) to claim a known substance induced psychosis is a “life long incurable genetic illness.”

    But the “mental health” industries today now believe a mania caused by an antidepressant is a “life long incurable genetic illness,” when anyone with a brain and ethics can understand that a drug induced illness is NOT a “genetic illness.” It’s an iatrogenic illness.

    The proposed changes are wildly stupid, unethical, and it may even be an illegal suggestion. Any lawyers have an answer regarding the legality of such a further expansion of psychiatric hegemony?

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  3. ‘Schizophrenia” (in this case) seems to be – when a person experiences a ‘Psychosis’ – goes onto ‘Antipsychotics’ – and then ‘Relapses’ if they come off the ‘Antipsychotics’.

    BUT if a ‘Well Person’ were to take ‘Antipsychotics’ for a period of time, they could easily end up in the same position. I ended up like this myself.

    To survive, I had to withdraw very carefully from the Strong Psychiatric Drugs – and compensate for the changes brought about by the presence of these drugs.
    And probably anyone can do this.

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  4. The study seems to take it for granted that continual psychosis as a result Cannibas consumption is the same as ‘Schizophrenia’ – but it’s not- it’s still Cannibas Psychosis.

    Continual alcohol psychosis as a result of consuming alcohol is also – alcohol psychosis – not ‘Schizophrenia’.

    The problem here is the ‘game playing’ of ‘Schizophrenia’.

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  5. If they were assessed for ‘psychosis’ rather than ‘mania’ (or ‘mood disorder’), it wouldn’t be very surprising that they were more likely to receive a schizophrenia diagnosis than a bipolar one.

    Or is the term ‘drug induced psychosis’ inclusive of ‘drug induced mania’ here? Does the paper have any breakdown of whether the patients’ initial episodes tended to be assessed as psychotic or manic? There are different criteria, aren’t there? I guess mood disorder type symptoms might be less likely to lead to hospitalization.

    I’ve argued that the prolonged use of neuroleptic drugs after first episodes of ‘psychosis’ may precipitate diagnoses of schizophrenia and lower long term recovery rates.


    I don’t deny that substances such as cannabis can be a contributory factor for such episodes. Although I think prescribed drugs can lead to episodes becoming more entrenched conditions.

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  6. Johnny’s Ambassadors based in Colorado is an excellent educational organization started by parents who lost their 19-year-old son to cannabis-induced psychosis. They are doing an awesome job in generating greater awareness of the devastating effects of synthetic high THC cannabis that’s destroying young people’s lives. Their upcoming in-person (and virtual) annual conference is in mid-July.

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  7. Cannabis-induced psychosis is a classical mistake of psychiatrists who neglect the fact that the cause of psychosis is cumulative childhood and teenage traumas.

    Here on Mad In America, there are several reports about that fact with kinks to the original academic papers, e.g.

    * https://www.madinamerica.com/2018/11/researchers-suggest-traumatic-experience-may-cause-psychotic-symptoms/

    * https://www.madinamerica.com/2018/04/study-finds-connection-trauma-psychosis-children/

    In the 1980s, Ronald K. Siegel published his book “Intoxication : The Universal Drive for Mind-Altering Substances”. He highlighted that humans as well as animals are attracted to psychoactive plants after a trauma. As said Los Angeles Times about that book : “A fascinating eye-opening book that challenges conventional wisdom.”

    His work was summarised by Johann Hari, author on Mad In America, in his 2015 blog “Why Animals Eat Psychoactive Plants”:

    * https://boingboing.net/2015/01/20/why-animals-eat-psychoactive-p.html

    So, in reality, first the person has to be traumatised by a terrible event.

    Second, that traumatised person instinctively consumes psychoactive plants and/or substances.

    Third, that consumption alerts family and friends that something does not go right in the mind of the sufferer.

    Fourth, psychiatrists neglecting the importance of traumas as cause of psychosis mistakenly conclude that cannabis is the cause, and they replace it with psych-drugs which are even more dangerous than cannabis.

    Several of my traumatised and diagnosed friends have told me that with cannabis and/or LSD, and/or other psychedelic substances, they had pleasure and felt better. With psych-drugs, they never have pleasure and they feel worse.

    No wonder that today, we hear more and more people talking about “psychedelic-assisted psychotherapy”.


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