Endometriosis and Mental Health: A Population-Based Cohort Study

Study Objective

To assess the association between endometriosis and the risk of mental health conditions.

Design

Matched population-based retrospective cohort study.

Setting

Ontario, Canada, from January 1, 2010, to July 1, 2022.

Patients or Participants

: Women aged 18 to 50 with a first-time diagnosis of endometriosis.

Interventions

N/A.

Measurements and Main Results

Endometriosis exposure was determined through either medical or surgical diagnostic criteria. A medical diagnosis was defined with diagnostic codes from outpatient and in-hospital visits, while 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 endometriosis diagnosis. Individuals with a mental health diagnosis in the two years before study entry were excluded.

A total of 107,832 individuals were included, 35,944 diagnosed with endometriosis (29.5% medically, 60.5% surgically, 10.0% medically with surgical confirmation) and 71,888 unexposed individuals. Over the study period, the incidence rate was 105.3 mental health events per 1,000 person-years in the endometriosis group compared to 66.5 mental health events per 1,000 person-year for unexposed individuals. Relative to the unexposed, the aHR for a mental health diagnosis was 1.28 (95% CI 1.24 – 1.33) in patients with medically diagnosed endometriosis, 1.33 (95% CI 1.16 – 1.52) in surgically diagnosed patients, and 1.36 (95% CI 1.2 – 1.6) in those diagnosed medically then confirmed surgically. The risk of receiving a mental health diagnosis was highest in the first year after endometriosis diagnosis and declined in subsequent years. The cumulative incidence of a severe mental health condition requiring hospital visits was 7.0% in endometriosis patients compared to 4.6% for unexposed individuals (HR 1.56, 95%CI 1.53-1.59).

Conclusion

Endometriosis is associated with an increased risk of mental health conditions. The elevated risk is particularly evident in the years immediately after diagnosis.