Cannabis use disorders linked to fewer digestive problems in schizophrenia patients but not in healthy people | Research

The takeaway

In a Danish national register study, cannabis use disorders were associated with 16% lower risk of gut-brain disorders and 30% lower risk of IBD in people with schizophrenia, but not in matched controls.

Psychiatrists, gastroenterologists treating patients with psychiatric comorbidity, and endocannabinoid researchers.

16% lower gut-brain disorder risk; 30% lower IBD risk in schizophrenia only

What the researchers found

Among 21,066 schizophrenia cases and 176,935 matched controls, cannabis use disorders in schizophrenia patients were associated with decreased risk of gut-brain interaction disorders (IBS, dyspepsia; HR 0.84, p=0.003) and inflammatory bowel disease (HR 0.70, p=0.045). These associations were not observed in healthy controls, suggesting an interaction specific to schizophrenia.

Why it matters

The endocannabinoid system modulates both gut function and inflammation. This large-scale finding that cannabis specifically protects against digestive disorders in schizophrenia (but not healthy people) could reveal unique therapeutic mechanisms.

The numbers in context

21,066 schizophrenia cases; 176,935 controls; gut-brain disorders HR 0.84 (p=0.003); IBD HR 0.70 (p=0.045) in basically adjusted model; no associations in controls.

How the study worked

Nationwide Danish register-based study using time-varying Cox regression in 21,066 schizophrenia patients and 176,935 age/sex-matched controls, adjusted for alcohol/substance use disorders and parental education.

What this study cannot tell us

Register-based (cannot determine cannabis type, dose, or route); cannabis use disorders are an extreme measure (does not reflect moderate use); IBD finding dropped below significance in fully adjusted model; unmeasured confounding possible.

How to read the evidence

Strong: large nationwide register study with matched controls and appropriate adjustments.

When this study was published

Published 2020.

The bigger picture

The schizophrenia-specific effect is intriguing. People with schizophrenia may have altered endocannabinoid systems that respond differently to cannabis, or cannabinoid effects on the gut-brain axis may depend on underlying psychiatric neurobiology.

Questions still open

What mechanism explains the schizophrenia-specific protective effect? Would targeted cannabinoid therapy reduce GI comorbidity in schizophrenia patients?

Common questions

Does cannabis protect against digestive problems?

Only in people with schizophrenia, according to this study. Cannabis use disorders were linked to fewer gut-brain disorders and less IBD in schizophrenia patients, but no such associations appeared in healthy controls.

Why would this only apply to schizophrenia patients?

The authors suggest this could reflect unique endocannabinoid system alterations in schizophrenia that create a different response to cannabis, potentially offering new treatment targets.

Read the original research

Cannabis use disorders may protect against certain disorders of the digestive organs in people with schizophrenia but not in healthy controls.

Psychological medicine, 50(3), 499-506

View on PubMed ↗Publisher’s paper ↗

Citation

Olesen, Julie Aamand; Posselt, Christine Merrild; Poulsen, Chalotte Heinsvig; Nordentoft, Merete; Hjorthøj, Carsten. (2020). Cannabis use disorders may protect against certain disorders of the digestive organs in people with schizophrenia but not in healthy controls.. Psychological medicine, 50(3), 499-506. https://doi.org/10.1017/S0033291719000370