Endometriosis, symptoms, and risk for depression and/or anxiety: a population-based retrospective study

Endometriosis is a chronic and inflammatory condition that often presents with chronic pelvic pain, dysmenorrhea, and dyspareunia, thus having important effects on quality of life. There are two proposed hypotheses to describe the known association between endometriosis and depression and anxiety: (1) the disease hypothesis, where the inflammatory nature of endometriosis is driving increased risk for depression and anxiety; and (2) the pain hypothesis, where it is the painful symptoms underlying the increased risk. We aimed to shed further light on these two hypotheses by assessing the risk for depression and/or anxiety in three groups of patients pathologically assessed for endometriosis: symptomatic endometriosis patients (Symp Endo), symptomatic patients with no pathological endometriosis diagnosis (Symp No Endo), and asymptomatic endometriosis patients (Asymp Endo).

This study included pathologically-confirmed endometriosis patients identified from the pathology records of Vancouver Coastal Health Authority between 2000 and 2008. These data were linked with population-based administrative health data for follow-up to 2017. Depression and anxiety were identified through diagnostics codes from health services use data and prescriptions for antidepressants. Bivariate analyses were performed to assess differences between groups. Cox proportional hazards models were run to generate hazard ratios for incident depression and/or anxiety between the groups.

There were 2729 people in Symp Endo, 585 in Symp No Endo, and 326 in Asymp Endo. Symp No Endo was more likely than Symp Endo to be visiting a physician for pelvic pain and to be taking prescription-level pain medications (p < 0.001). After adjusting for several covariates, Symp No Endo had a significantly higher risk of incident depression and/or anxiety (adjusted HR: 1.23, 95% CI: 1.06-1.41) compared to Symp Endo. There was no statistically significant difference in risk of depression and/or anxiety between Symp Endo and Asymp Endo (adjusted HR: 0.94, 95% CI: 0.76-1.17).

These results point toward the pain focused hypotheses as Symp No Endo patients were at higher risk for depression/anxiety than the Symp Endo group. However, the results also suggest the disease hypothesis is at play, because the Symp Endo and Asymp Endo groups were at the same level of risk for depression/anxiety.