Rise of Undiagnosed Major Depressive Disorder Post-COVID-19 Pandemic in Europe

OBJECTIVES: To compare rates of diagnosed depression and undiagnosed depression among adults in the EU4 (France, Germany, Spain, and Italy) and the United Kingdom (UK), from pre-COVID-19 to post COVID-19 years using a representative general population survey.

METHODS: Data from the 2011(N=57,512), 2018(N=62,000), and 2021(N=62,028) EU4+UK National Health and Wellness Survey, a nationally-representative, cross-sectional online survey of adults (aged ≥18), was analyzed. Respondents were classified as having major depressive syndrome (MDS) based on the Patient Health Questionnaire 9-item depression score (PHQ-9). MDS included 5 or more of the 9 depressive symptom criteria have been present at least “more than half the days” in the past 2 weeks, and 1 of the symptoms is depressed mood or anhedonia. Those who self-reported having depression that was diagnosed by a physician were classified as diagnosed. Those who did not self-report experiencing depression were classified as undiagnosed. Descriptive statistics were conducted.

RESULTS: Diagnosed MDS in pre-COVID-19 years, 2011 and 2018 were 3.1%(n=1,799) and 3.7%(n=2,285), respectively. For those same years, those receiving a prescription treatment for depression were 65.1%(n=1,172) and 63.6%(n=1,454). In post COVID-19 2021, diagnosed MDS was 3.5%(n=2,175) and those on treatment was 61.8%(n=1,345). In 2011, using PHQ-9 to screen for MDS the undiagnosed rate was 3.5%(n=1,997). This rate increased to 4.2%(n=2,601) in 2018 and to 6.2%(n=3,834) in 2021. In 2021, among those with undiagnosed MDS, 70.1% had moderately-severe to severe depression.

CONCLUSIONS: While rates of diagnosed MDS and treatment remained consistent from pre-COVID-19 to post COVID-19, the rates of undiagnosed MDS increased 1.5 times from the year just prior to COVID-19 to post COVID-19. These results reveal the underlying problem with MDS – many individuals are undiagnosed and untreated even as they experience severe depression. More than ever before, now in this post COVID-19 environment, access to mental health support and therapists are needed.