Endometriosis and the mental health burden: a registry-based study of redeemed prescriptions and psychiatric hospital contacts before and after diagnosis of endometriosis.

STUDY QUESTION: Do women with endometriosis have a higher use of antidepressants and anxiolytics, and more frequent psychiatric hospital contacts due to depression or anxiety, before and after receiving their endometriosis diagnosis, compared with women without endometriosis? SUMMARY ANSWER: Women with an endometriosis diagnosis redeemed more prescriptions for antidepressants and anxiolytics and had more psychiatric hospital contacts due to depression or anxiety both before and after endometriosis diagnosis compared with women without endometriosis. WHAT IS KNOWN ALREADY: Endometriosis is associated with an increased risk of anxiety and depression, but evidence on patterns before and after diagnosis is limited. STUDY DESIGN, SIZE, DURATION: This national, retrospective, registry-based study included 136 842 Danish women aged 15-55 years between 1 January 2000 and 31 December 2019. Each woman was followed for up to 10 years before and 10 years after the index date. PARTICIPANTS/MATERIALS, SETTING, METHODS: We identified 22 807 women with a first-time hospital-based diagnosis of endometriosis using density sampling. Each woman with endometriosis was matched on age at the date of diagnosis (index date) to five women without diagnosed endometriosis (n = 114 035). Information on redeemed prescriptions and psychiatric hospital contacts was obtained from national registries and compared using negative binomial regression. MAIN RESULTS AND THE ROLE OF CHANCE: Women with an endometriosis diagnosis redeemed more prescriptions for antidepressants and anxiolytics and had more psychiatric hospital contacts due to depression or anxiety in the 20-year study window. Adjusted incidence rate ratios (IRRs) for antidepressants were 1.29 (95% CI 1.23-1.36) before and 1.40 (95% CI 1.34-1.47) after the index date, when adjusting for age, region of residence, highest educational level, household type, labor market affiliation, origin, and parity. For anxiolytics, IRRs were 1.16 (95% CI 1.05-1.28) before and 1.46 (95% CI 1.29-1.64) after the index date. For psychiatric hospital contacts, IRRs were 1.28 (95% CI 1.09-1.49) before and 1.41 (95% CI 1.22-1.63) after the index date. The association for antidepressants was quite stable over the study period, while the association for anxiolytics showed a significant increase right before the index date, and the associations for psychiatric hospital contacts increased around 5 years before the index date. LIMITATIONS, REASONS FOR CAUTION: It was not possible to include women who were treated for suspected endometriosis in general practice or women diagnosed with endometriosis solely by private gynecologists. Therefore, the results are only applicable to hospital-based diagnoses of endometriosis. Not all women with depression or anxiety receive pharmacological treatment or hospital-based care. Hence, we might not have identified all women with depression and anxiety. However, we expect this under-ascertainment of depression and anxiety to be similar among women with and without endometriosis and thereby independent of endometriosis diagnosis. WIDER IMPLICATIONS OF THE FINDINGS: These findings align with existing literature but provide new insights into the mental health burden in the pre-diagnostic period. Future studies should investigate the causal pathways and potential mediating factors of the association. A better understanding of the link between endometriosis, depression, and anxiety and improved awareness can help healthcare professionals identify affected women more easily and improve treatment strategies. STUDY FUNDING/COMPETING INTEREST(S): This article is supported by grants from the project 'Finding Endometriosis using Machine Learning' (FEMaLe/101017562) funded by the European Union's Horizon 2020 research and innovation program, and from Helsefonden (21-B-0141). The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.