Endometriosis and mental health: a population-based cohort study

Endometriosis is a chronic gynecologic disorder that leads to considerable pain and a reduced quality of life. Although its physiological manifestations have been explored, its impact on mental health is less well defined. Existing studies of endometriosis and mental health were conducted within diverse healthcare landscapes with varying access to care and with a primary focus on surgically diagnosed endometriosis. A single-payer healthcare system offers a unique environment to investigate this association with fewer barriers to access care while considering the mode of endometriosis diagnosis.

Our objective was to assess the association between endometriosis and the risk for mental health conditions and to evaluate differences between patients diagnosed medically and those diagnosed surgically.

A matched, population-based retrospective cohort study was conducted in Ontario and included patients aged 18 to 50 years with a first-time endometriosis diagnosis between January 1, 2010, and July 1, 2020. Endometriosis exposure was determined through either medical or surgical diagnostic criteria. A medical diagnosis was defined by the use of the corresponding International Classification of Disease diagnostic codes from outpatient and in-hospital visits, whereas a surgical diagnosis was identified through inpatient or same-day surgeries. Individuals with endometriosis were matched 1:2 on age, sex, and geography to unexposed individuals without a history of endometriosis. The primary outcome was the first occurrence of any mental health condition after an endometriosis diagnosis. Individuals with a mental health diagnosis in the 2 years before study entry were excluded. Cox regression models were used to generate hazard ratios with adjustment for hysterectomy, salpingo-oophorectomy, infertility, pregnancy history, qualifying surgery for study inclusion, immigration status, history of asthma, abnormal uterine bleeding, diabetes, fibroids, hypertension, irritable bowel disorder, migraines, and nulliparity.

A total of 107,832 individuals were included, 35,944 with a diagnosis of endometriosis (29.5% medically diagnosed, 60.5% surgically diagnosed, and 10.0% medically diagnosed with surgical confirmation) and 71,888 unexposed individuals. Over the study period, the incidence rate was 105.3 mental health events per 1000 person-years in the endometriosis group and 66.5 mental health events per 1000 person-year among unexposed individuals. Relative to the unexposed individuals, the adjusted hazard ratio for a mental health diagnosis was 1.28 (95% confidence interval, 1.24-1.33) among patients with medically diagnosed endometriosis, 1.33 (95% confidence interval, 1.16-1.52) among surgically diagnosed patients, and 1.36 (95% confidence interval, 1.2-1.6) among those diagnosed medically with subsequent surgical confirmation. The risk for receiving a mental health diagnosis was highest in the first year after an endometriosis diagnosis and declined in subsequent years. The cumulative incidence of a severe mental health condition requiring hospital visits was 7.0% among patients with endometriosis and 4.6% among unexposed individuals (hazard ratio, 1.56; 95% confidence interval, 1.53-1.59).

Endometriosis, regardless of mode of diagnosis, is associated with a marginally increased risk for mental health conditions. The elevated risk, particularly evident in the years immediately following the diagnosis, underscores the need for proactive mental health screening among those newly diagnosed with endometriosis. Future research should investigate the potential benefits of mental health interventions for people with endometriosis with the aim of enhancing their overall quality of life.