Journal Club: Cannabinoids and endometriosis

Estimated reading time: 4 minutes

Issue five of Grow Pharma’s Journal Club, explores the latest research on the role of cannabinoids in endometriosis.

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For this edition of the journal club, the focus is on endometriosis.

Endometriosis affects almost 200 million women globally, with the main symptoms being chronic pelvic pain, fatigue, and dysmenorrhea (period pain), often alongside co-morbid gastrointestinal (GI) and psychiatric issues [1].

Given the growing body of evidence supporting cannabinoid use particularly for chronic pain2, it is not surprising that women with endometriosis are increasingly turning to cannabis to help alleviate their symptoms.

Indeed, several recent surveys have reported that cannabis use amongst women with endometriosis is common, with the majority of patients reporting improvements in their condition [3,4,5].

In this issue of the Journal Club, two recent studies focusing on cannabinoids in endometriosis are highlighted.

The first study is a pre-clinical trial investigating the effects of once daily 2mg/kg THC for 28 days in a mouse model of endometriosis.

The mouse model reproduced the ectopic endometrial growths associated with the condition, alongside some of the behavioural alterations commonly experienced – pelvic pain, anxiety, and memory impairments. The effects of THC in endometriosis mice were compared to those in healthy mice, as well as to placebo.

Overall, the study found that THC reduced pain in endometriosis mice, but no difference in anxiety-like behaviour was observed (perhaps not surprising given that most cannabis studies reporting anxiolytic effects involve CBD6,7). THC also improved cognitive performance in endometriosis mice, but had the opposite effect in healthy mice, suggesting THC exerts different effects under chronic inflammatory conditions.

Interestingly, these behavioural manifestations correlated with a decrease in the size of the ectopic endometrium in THC-exposed mice.

In summary, this pre-clinical study in mice showed that THC has promise in relieving pain, restoring cognitive function, and even in reducing the size of endometrial cysts, calling for clinical trials to be conducted investigating the possible benefits of THC in women with endometriosis. 

The second study is a retrospective trial of 252 patients taking cannabis for endometriosis.

The app Strainprint was used by patients to record their symptoms before and after each cannabis administration. In total, 16,193 sessions were recorded, with each patient submitting data for a mean duration of 5.5 months.

Overall, cannabis was reported to have a positive effect on pain, mood, and GI symptoms. Inhaled forms had higher efficacy for pain, while oral forms were superior for mood and GI symptoms.

However, this observation was confounded by inhaled forms on average containing more THC and oral forms on average containing more CBD. In summary, the study found that women with endometriosis reported improvements in pelvic pain, GI issues and mood, with effectiveness differing depending on the method of ingestion and the THC/CBD content.

For an up-to-date overview of medical cannabis research in endometriosis, refer to Marcu et al 8. 

If you are a doctor and would like to discuss either of the clinical papers featured in this edition of the journal club or the broader medical cannabis literature, please reach out on luca.marelli@growbiotech.com

References:

1 Sinclair.J et al. Effects of cannabis ingestion on endometriosis-associated pelvic pain and related symptoms (2021). PLoS One 16(10): e02589402 NASEM. The health effects of cannabis and cannabinoids: the current state of evidence and recommendations for research (2017). Washington, DC. The National Academies Press 3 Armour.M et al. Self-management strategies amongst Australian women with endometriosis: a national online survey (2019). BMC Complement Altern Med 19:17 4 Reinert.A et al. Self-reported efficacy of cannabis for endometriosis pain (2019). Open communications 26(7), S72 5 Carrubba.A et al. Use of cannabis for self-management of chronic pelvic pain (2021). J Womens Health 30(9):1344-1351  6 Bergamaschi.M et al. CBD reduces the anxiety induced by simulated public speaking in treatment-naïve socla phobia patients (2011). Neuropsychopharmacology 36(6)1219-1226 7 Masataka.N. Anxiolytic effects of repeated cannabidiol treatment in teenagers with social anxiety disorders (2019). Front Psychol 10:2466 8 Marcu.I et al. Cannabinoids and chronic pelvic pain in women: focus on endometriosis (2021).  Journal of Endometriosis and Pelvic Pain Disorders 13(3):155-165