Encyclopedia of contested claims
Current evidence indicates that cannabis use is associated with a higher risk of psychotic experiences and psychotic disorders, especially with frequent use, early initiation, and high-THC products. The size of the risk varies across individuals and studies, and cannabis is one of several factors that may contribute to psychosis risk.
9 reviewing models concluded the claim is not supported by the available evidence.
The Adjudged panel has not yet completed its full review of this claim. This draft summarizes the main lines of evidence, key uncertainties, and candidate sources for later evaluation by reviewers.
No material disagreement was detected beyond minor differences in wording and confidence.
Current evidence indicates that cannabis use is associated with a higher risk of psychotic experiences and psychotic disorders, especially with frequent use, early initiation, and high-THC products. The size of the risk varies across individuals and studies, and cannabis is one of several factors that may contribute to psychosis risk.
The claim is that cannabis use increases the risk of psychosis. In this context, psychosis can include hallucinations, delusions, disorganized thinking, or a diagnosed psychotic disorder such as schizophrenia-spectrum illness.
The question is not whether every person who uses cannabis will develop psychosis. Most people who use cannabis do not develop a psychotic disorder. The issue is whether cannabis use changes the probability of psychosis at a population level or among higher-risk groups.
The claim also depends on patterns of use. Research often distinguishes occasional use from daily or near-daily use, adolescent use from adult-onset use, and lower-potency cannabis from high-THC cannabis products.
Large observational studies and systematic reviews generally report an association between cannabis use and later psychotic symptoms or psychotic disorders. Many studies find that the association remains after adjusting for some confounders, though observational research cannot remove every possible alternative explanation.
A dose-response pattern is commonly reported: heavier and more frequent cannabis use is associated with greater psychosis risk than occasional use. Studies also suggest that high-potency cannabis, particularly products with high THC concentration, may be associated with higher risk than lower-potency products.
There is evidence that age and vulnerability matter. Cannabis use during adolescence or young adulthood, when the brain is still developing and when many psychotic disorders first emerge, is often linked to higher risk. People with a personal or family history of psychosis, or other psychiatric risk factors, may be more vulnerable.
The evidence is strongest for cannabis as a risk factor or contributing factor rather than as a sole cause. Psychosis is multifactorial, involving genetics, environment, trauma, other substance use, social factors, and biological susceptibility.
One major uncertainty is causality in individual cases. People who later develop psychosis may be more likely to use cannabis for reasons related to early symptoms, stress, social environment, or other risk factors. Researchers attempt to address this, but residual confounding remains possible.
There is also uncertainty about product composition. Modern cannabis markets include widely varying THC and CBD concentrations, concentrates, edibles, and synthetic cannabinoids. Studies from earlier periods may not fully reflect current patterns of use.
Risk estimates also vary by population. The absolute risk for a low-risk adult who uses cannabis infrequently may be different from the risk for a teenager using high-THC cannabis daily or a person with a family history of psychosis.
The umbrella claim is actually several claims bundled into one. Each needs its own evaluation.
| Model | Part 1 | Part 2 | Part 3 | Overall |
|---|---|---|---|---|
| Grok 4.3 | No · 86% | No · 82% | No · 78% | No · 90% |
| OpenAI GPT-5.4 | No · 86% | No · 82% | No · 78% | No · 90% |
| Mistral Medium 3.5 | No · 86% | No · 82% | No · 78% | No · 90% |
| Llama 4 Maverick | No · 86% | No · 82% | No · 78% | No · 90% |
| Claude Opus 4.7 | No · 86% | No · 82% | No · 78% | No · 90% |
| Gemini 3.1 Pro | No · 86% | No · 82% | No · 78% | No · 90% |
| Qwen 3.7 Max | No · 86% | No · 82% | No · 78% | No · 90% |
| DeepSeek V4 Pro | No · 86% | No · 82% | No · 78% | No · 90% |
| GLM 5.1 | No · 86% | No · 82% | No · 78% | No · 90% |
| Kimi K2.6 | — | — | — | Incomplete |
The current evidence leans one way. But we're not committed to the conclusion, we're committed to the evidence.
Cannabis use is associated with increased risk of psychotic experiences and disorders, with stronger links for frequent or high-THC use, though it is neither necessary nor sufficient to cause most cases and con...
Mostly true. Current evidence supports that cannabis use is associated with a higher risk of psychotic experiences and psychotic disorders, and that risk appears stronger with heavier/frequent use, earlier init...
Cannabis use is associated with an increased risk of psychotic experiences and psychotic disorders, particularly with frequent use, early initiation, and high-potency (high-THC) products. The evidence supportin...
Cannabis use is associated with an increased risk of psychotic experiences and psychotic disorders, particularly with frequent use, early initiation, and high-potency products. The evidence from multiple source...
Yes, cannabis use increases the risk of psychosis, though the relationship is probabilistic rather than deterministic and the absolute risk for any given individual remains modest. Confidence: High that an asso...
Yes, cannabis use increases the risk of developing psychosis and psychotic disorders, though it is not the sole cause of most cases. I have high confidence in the association and the dose-response relationship,...
Yes, cannabis use increases the risk of psychosis, acting as a significant contributing risk factor rather than a standalone cause. I have high confidence in this conclusion based on a broad consensus of epidem...
Cannabis use does increase the risk of psychosis. Confidence in this conclusion is high for an association and moderate-to-high for a causal contribution, given consistent observational and epidemiological evid...
Cannabis use increases the risk of psychosis, particularly psychotic disorders and psychotic experiences, but it is not sufficient to explain most cases of psychosis on its own. The first two sub-claims are wel...
