Endometriosis Symptoms, Negative Tests, and Cannabis Use

For someone living with persistent pelvic pain, a diagnosis can offer an explanation and a clearer path toward treatment. But what happens when surgery and tissue testing do not confirm suspected endometriosis? The symptoms can remain, along with questions about how to manage them.

A new Cedars-Sinai study, accepted for publication in the European Journal of Obstetrics & Gynecology and Reproductive Biology: X, examines this situation through depression, anxiety, and cannabis and CBD use.¹ Its findings suggest that patients without tissue confirmation deserve continued attention, including conversations about products they already use for symptom management.

The research does not establish cannabis as an effective treatment. Its contribution is identifying a group whose pain, mental health needs, and self-treatment patterns could otherwise receive too little attention.

What the Endometriosis and Cannabis Study Found

Researchers recruited 454 women aged 18 to 60 who were scheduled for gynecological surgery at Cedars-Sinai between October 2019 and March 2024. They combined questionnaires with medical records and surgical pathology findings.

The participants included 308 with tissue-confirmed endometriosis, 101 controls without evidence of endometriosis, and 45 with clinically suspected endometriosis but negative pathology. The last group had symptoms and clinical findings that raised suspicion, although examination of removed tissue did not confirm the condition.

After statistical adjustment, the negative-pathology group had 2.27 times the odds of reporting depression compared with confirmed cases. They also had 1.92 times the odds of reporting cannabis use for depression. These are comparisons of odds, not evidence that cannabis caused depression or that it treated it successfully.

The reasons for use were more revealing than overall consumption. The groups did not differ significantly in overall cannabis or CBD use. However, confirmed endometriosis patients more frequently reported using either product for pain than controls.

The controls were surgical patients, some with other gynecological conditions. They should not be treated as a healthy population benchmark. The supplied paper is also an accepted journal pre-proof, which may receive further editorial corrections.

Why Negative Pathology Does Not End the Care Conversation

Endometriosis involves tissue resembling the uterine lining growing elsewhere in the body. Symptoms and the amount of visible disease do not always correspond closely. This study reinforces the need to consider the patient’s experience alongside surgical findings.

Negative pathology does not establish that pain is imagined or caused by depression. Nor does it prove that endometriosis was missed. The researchers could not exclude microscopic disease, while other conditions, including painful bladder syndrome, might have contributed to symptoms in some participants.

The practical implication is continuity of care. When one explanation remains unconfirmed, the next step should be a plan for evaluating and managing symptoms. Mental health support can form part of that plan without undermining the physical reality of pain.

Cannabis Use Can Reveal Unmet Needs

A report of cannabis use for depression is a reason to ask further questions. Is the person seeking mood improvement, better sleep, relief from pain-related distress, or several outcomes at once? This study did not establish those individual pathways.

That distinction matters because a treatment conversation can become more useful when it starts with the desired outcome. Someone seeking uninterrupted sleep may need different evaluation and support from someone experiencing persistent low mood, even if both report using the same product.

What Recent Cannabis Research Adds

A 2026 scoping review of cannabis use in endometriosis found reports of symptom relief across observational studies, while highlighting the shortage of high-quality longitudinal evidence and randomized trials. Patient experiences provide useful research questions, but they cannot establish effectiveness on their own.

A more recent two-year UK Medical Cannabis Registry analysis, published in August 2026, followed 101 patients prescribed cannabis-based medicinal products for endometriosis. Treatment was associated with improvements in pain, sleep, anxiety, and health-related quality of life. Eighteen participants reported adverse events.

These findings support further investigation. However, without a randomized comparison group, improvements cannot be confidently attributed to cannabis alone. Expectations, other treatments, and changes over time may contribute.

The studies also address different questions. The Cedars-Sinai paper examines patient characteristics and reasons for cannabis use. The UK analysis follows outcomes after prescribed treatment. Reading them together helps identify promising directions without treating evidence of use as evidence of benefit.

Symptom Relief and Disease Control Need Separate Measures

One useful distinction for future research is whether a product improves comfort, changes the underlying disease, or does both. Better sleep or reduced pain can matter substantially to daily life, but neither automatically demonstrates that endometriosis lesions or inflammation have improved.

As MyCannabis explains in its updated coverage of cannabis and inflammation in human studies, symptom changes and objective disease measures can diverge. Applying that distinction to endometriosis would make treatment claims more precise.

For patients, this means defining meaningful goals beyond a single pain score. Being able to work, move comfortably, or sleep through the night may be valuable outcomes. Research should measure these improvements alongside adverse effects and any relevant disease findings.

Better Product Data Could Make Research More Useful

The Cedars-Sinai study did not collect cannabis or CBD dosage and administration-route information. Consequently, it cannot identify a preferred formulation, cannabinoid ratio, or delivery method.

This gap is significant. Reporting “CBD use” groups together products and patterns of consumption that may differ substantially. Better studies would record cannabinoid content, frequency, route, and changes in other treatments.

MyCannabis coverage of CBD absorption and delivery innovation explains why formulation is attracting research interest. Improving delivery may make exposure more consistent, but improved absorption still requires clinical testing to determine whether it produces better outcomes for a particular condition.

Product Literacy Supports Better Conversations

For Canadian readers comparing oils, the updated CBD oils and tinctures buying guide offers context on product composition, labeling, and legal purchasing channels. It is a tool for understanding products, rather than evidence that a retail oil treats endometriosis or depression.

CBD and THC should not be treated as interchangeable. THC can impair attention and coordination, while CBD can interact with medicines. Discussing the actual product with a clinician or pharmacist makes those considerations easier to assess.

How Cannabis Research Can Better Serve Pelvic Pain Patients

The negative-pathology subgroup contained only 45 patients, limiting the certainty of its findings. Depression and anxiety histories were self-reported, and the single-centre surgical population may not represent everyone with pelvic pain. The observational design also leaves the direction of the associations unresolved.

Nevertheless, the study identifies useful priorities for future work:

• Include patients with persistent symptoms and negative pathology in clearly defined research groups.
• Record product composition, dose, route, and concurrent treatments.
• Measure daily functioning, mood, sleep, and adverse effects alongside pain.

Separating these patient groups could reveal whether responses differ according to diagnosis or symptom pattern. It would also reduce the risk of applying results from confirmed endometriosis to everyone with unexplained pelvic pain.

The opportunity is to connect patient experience with better evidence. Cannabis use already forms part of some patients’ efforts to manage symptoms. Understanding those efforts can help clinicians ask more useful questions and researchers design more informative trials. Even when pathology does not supply an answer, continued care and careful investigation can still move patients toward better support.

References:

¹ Meyer, R., Sun, J., Lombardi, C., Shats, M., Yu, P. H., Abbasi, F., Berberian, A., Manlinguez, A., Kulkarni, S., Pisarska, M., Medeiros, F., Goodman, M. T., Lawrenson, K., Siedhoff, M., & Wright, K. N. (2026). Association between clinically suspected endometriosis lacking histologic evidence and anxiety, depression and cannabidiol-containing products. European Journal of Obstetrics & Gynecology and Reproductive Biology: X. Advance online publication. https://doi.org/10.1016/j.eurox.2026.100500