Prevalence of Mental Disorders, Suicidal Ideation and Suicides in the General Population Before and During the COVID-19 Pandemic in Norway. A Population-Based Repeated Cross-Sectional Analysis from the HUNT Study and the Norwegian Cause of Death Registry

Background: Self-report data indicate a deterioration of population mental health in many countries during the COVID-19 pandemic. A Norwegian epidemiological diagnostic psychiatric interview survey was conducted from January to September 2020, allowing for comparison of current prevalence of mental disorders from before through different pandemic phases. Prevalence of suicide deaths were compared between 2020 and 2014-2018. Methods: Participants from the Trondelag Health Study (HUNT) in Trondheim were recruited through repeated probability sampling. Using the Composite International Diagnostic Interview (CIDI 5.0) (n=2,154), current prevalence of mental disorders was examined in repeated cross-sectional analyses. Data on suicide was retrieved from the Norwegian Cause of Death Registry and compared for the first phase of the pandemic with the same months 2014-2018.  Findings: Prevalence of mental disorders decreased significantly from the pre-pandemic phase (January 28th to March 11th 2020; 15·3% [95% CI 12·4-18·8]) to the first pandemic phase (March 12th – May 31st ; 8·7% [6·8-11·0]) and was fairly stable through the interim phase (June 1st July 31st ; 14·2% [11·4-17·5]) and the second phase (August 1st -September 18th ; 11·9% [9·0-15·6]). Suicidal ideation was non-significantly (n.s) increased during the pandemic. Suicide deaths were 15% lower (n.s) in March-May 2020 (n=140) compared with the same months pooled over 2014-2018 (n=165).     Interpretation: We found no increase in mental disorders or suicides during the COVID-19 pandemic up through early autumn 2020. COVID-19 related mortality, transmission rates, intensity and implementation of measures and lockdowns have been less severe in Norway than many other countries and could account for these results. Funding: None Declaration of Interests: Dr. Hotopf reports grants from European Commission IMI/EFPIA, grants from National Institute of Health Research, grants from Medical Research Council, and grants from Economic and Social Research Council outside the submitted work. In the past 3 years, Dr. Kessler was a consultant for Datastat, Inc., Sage Pharmaceuticals, and Takeda. The authors Dr. Knudsen, Dr. Gustavson, Dr. Krokstad, Dr. Skogen, Dr. Stene-Larsen, Dr. Overland and Dr. Reneflot report no conflict of interest. Ethics Approval Statement: The survey was a collaboration between the Norwegian Institute of Public Health (NIPH) and the HUNT Research Centre and approved by the Regional Committee for Medical Research Ethics (2017/28/REK midt).