Cannabis Users Have More Pain After Surgery
What Researchers Found About Chronic Pain and Cannabis
The Study at a Glance
Published
Journal of Obstetrics and Gynaecology Canada, 2022
Researchers
Queen's University (Canada)
Study Type
Observational StudyParticipants
654 patients · 2 years
Key Finding
Cannabis users had significantly worse outcomes after surgery: higher pain scores, higher opioid consumption, and more sleep disturbance than non-users. This suggests preoperative cannabis use is a risk factor for postoperative pain.
Key Finding: Cannabis users had significantly worse outcomes after surgery: higher pain scores, higher opioid consumption, and more sleep disturbance than non-users. This suggests preoperative cannabis use is a risk factor for postoperative pain.
What Researchers Studied About Chronic Pain and Cannabis
Does using cannabis before surgery help or hurt pain control afterward? Many patients assume cannabis will help with pain, but what does the evidence show?
This study examined postoperative outcomes in patients who did and did not use cannabis before gynecologic cancer surgery—providing real-world evidence on this important question.
The results may surprise many cannabis users planning for surgery.
How This Observational Study Was Conducted
Researchers conducted a retrospective study:
• Reviewed records of 654 gynecologic oncology surgery patients • Compared 64 cannabis users vs 590 non-users • Used propensity score matching to control for confounders • Measured pain scores at 12 and 36 hours after surgery • Tracked opioid consumption, hospital stay, and sleep disturbance
Chronic Pain Treatment Results
The Main Results:
- 1Pain scores HIGHER in cannabis users at 12 hours (6 vs 4 on 0-10 scale)
- 2Pain scores HIGHER at 36 hours (5 vs 4)
- 3Opioid consumption HIGHER at 12 hours (20 vs 10 mg morphine equivalent)
- 4Opioid consumption HIGHER at 36 hours (40 vs 30 mg)
- 5Sleep disturbance 3.3x more common in cannabis users
- 6Cannabis use appears to be a RISK FACTOR for postoperative pain
By the Numbers
| Statistic | What It Means |
|---|---|
| 50% | higher median pain scores in cannabis users |
| 2x | opioid consumption at 12 hours after surgery |
| 3.3x | more sleep disturbance in cannabis users |
| 654 | patients studied |
higher median pain scores in cannabis users
opioid consumption at 12 hours after surgery
more sleep disturbance in cannabis users
patients studied
What This Means for Chronic Pain Patients
If you use cannabis and have surgery planned, this study has important implications:
The surprising findings: • Cannabis users had HIGHER pain scores after surgery, not lower • Cannabis users needed MORE opioids, not fewer • Sleep disturbance was much more common in cannabis users
What this might mean: • Regular cannabis use may change how your body responds to pain • You may develop tolerance that makes pain harder to control • Cannabis may not be the opioid-sparing solution some hope for
What to discuss with your surgical team: • Disclose your cannabis use before surgery • Ask about pain management planning • Understand that you may need more aggressive pain control • Don't assume cannabis will help—it may make things harder
Important caveats: This was one observational study in gynecologic surgery patients. More research is needed to understand why cannabis users have worse pain outcomes.
Quick Answers: Chronic Pain and Cannabis
Direct answers based on the findings of this study:
Research Summary: Answers are based on published peer-reviewed studies and represent research findings, not medical recommendations. Individual results may vary. Always consult a healthcare provider before making treatment decisions.
Does weed make surgery recovery harder?
Yes—marijuana users had 50% higher pain scores after surgery (6 vs 4 on 0-10 scale), needed twice the opioids, and had 3x more sleep problems according to a 2022 study of 654 patients (Hickey et al.).
Source: Hickey et al., Journal of Obstetrics and Gynaecology Canada, 2022 (PMID: 35202866)
Do pot smokers need more pain meds after surgery?
Yes, significantly more. Cannabis users needed twice the opioids at 12 hours after surgery (20 vs 10 mg morphine equivalent) and more at 36 hours too (40 vs 30 mg). Tell your surgeon if you use marijuana.
Source: Hickey et al., Journal of Obstetrics and Gynaecology Canada, 2022 (PMID: 35202866)
Should I stop smoking weed before surgery?
Discuss with your surgeon. Research shows cannabis users have worse pain control after surgery—higher pain scores, more opioid needs, worse sleep. Your surgical team needs to know so they can plan your pain management.
Source: Hickey et al., Journal of Obstetrics and Gynaecology Canada, 2022 (PMID: 35202866)
This is educational content, not medical advice
The research summarized here is for informational purposes only. Individual results may vary, and what works in studies may not work the same way for everyone. Always consult with a qualified healthcare provider before making changes to your treatment plan or starting medical cannabis therapy.
Important Limitations
This study has some caveats to keep in mind when interpreting the results:
- Retrospective observational study (can't prove causation)
- Single surgical specialty (gynecologic oncology)
- Couldn't control for cannabis dose, frequency, or type
- Self-reported cannabis use may be underreported
- Other factors may explain differences
The Bottom Line on Cannabis for Chronic Pain
This study challenges the assumption that cannabis helps with surgical pain. Cannabis users had significantly higher pain scores, required more opioids, and had worse sleep after surgery than non-users. While the study can't prove causation, it suggests preoperative cannabis use may be a risk factor for postoperative pain. If you use cannabis and have surgery planned, disclose this to your surgical team so they can plan your pain management accordingly.
Do You Qualify for Medical Marijuana?
If you're living with Chronic Pain, you may qualify for a medical marijuana card. Our licensed physicians can evaluate you from home via telehealth.
Related Research & Resources
Related Research
Condition Research
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Source
Wiseman LK, Mahu IT, Mukhida K "The Effect of Preoperative Cannabis Use on Postoperative Pain Following Gynaecologic Oncology Surgery" Journal of Obstetrics and Gynaecology Canada. 2022. DOI: 10.1016/j.jogc.2022.01.018
Important Information
Not Medical Advice: This research summary is for educational purposes only. It should not be used to diagnose, treat, cure, or prevent any disease or medical condition. Always consult a qualified healthcare provider before starting or changing any treatment.
Individual Variation: Research findings represent group averages. Your individual response to cannabis may differ based on genetics, other medications, underlying conditions, and many other factors.
Last reviewed: January 24, 2026
Important Notices
Research Summary Disclaimer
This content represents our interpretation of published scientific research for educational purposes. It should not be used to make treatment decisions without consulting a qualified healthcare provider. Individual results may vary from study findings.
FDA Notice
These statements have not been evaluated by the FDA. Cannabis is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not approved cannabis for any medical condition except specific prescription medications.
Copyright & Fair Use
Research summaries are provided under fair use (17 U.S.C. § 107) for educational purposes. We provide brief summaries with attribution, not full reproductions. All studies remain the intellectual property of their respective authors and publishers.
Data Sources
Study information sourced from PubMed®, U.S. National Library of Medicine. Inclusion does not imply endorsement by NLM, NIH, or the federal government.
For complete information, see our Terms of Use and Research Content Policy.
FAQs: Cannabis for Chronic Pain
Do cannabis users have more pain after surgery?
Yes, users report more pain. Cannabis users had 50% higher median pain scores at 12 and 36 hours after surgery, needed more opioids, and had more sleep disturbance than non-users.
Does cannabis help with postoperative pain?
No, it may make pain harder to control. Cannabis users required twice the opioids at 12 hours after surgery. The authors concluded cannabis use is a "risk factor for postoperative pain."
Should I stop cannabis before surgery?
Discuss this with your surgical team. This study shows cannabis users have worse pain outcomes, so your team needs to know about your use to plan appropriate pain management.