Christian Rauschenberg, MSc^{1, 2}, Anita Schick, PhD¹, Christian Goetzl, MA³, Susanne Roehr, PhD⁴, Prof. Steffi G. Riedel-Heller, MD⁴, Georgia Koppe, PhD^{5, 6}, Prof. Daniel Durstewitz, PhD⁵, Silvia Krumm, PhD³, Prof. Ulrich Reininghaus, PhD<sup>1, 7, 8

1</sup> Department of Public Mental Health, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ² Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands; ³ Department of Psychiatry II, University of Ulm and BKH Guenzburg, Ulm, Germany; ⁴ Institute of Social Medicine, Occupational Health and Public Health (ISAP), Medical Faculty, University of Leipzig, Leipzig, Germany; ⁵ Department of Theoretical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ⁶ Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; ⁷ Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK; ⁸ ESRC Centre for Society and Mental Health, King´s College London, London, UK

Background
As of March 2020, most European countries have adopted a range of public health measures to lower the transmission of SARS-CoV-2 coronavirus. Physical distancing and quarantine have been amongst the most important non-pharmacological measures to reduce infection rates of coronavirus disease 2019 (COVID-19). These preventive measures may have a profound impact on public mental health. Initial reports on the negative psychosocial correlates of the current COVID-19 pandemic are largely in line with findings on earlier epidemics and increased depression, anxiety, and loneliness have been reported. Digital interventions may help to mitigate these effects. The current study aimed to investigate the associations between social isolation, COVID-19-related cognitive preoccupation, worries, and anxiety, objective social risk indicators, psychological distress as well as use of, and attitude towards, digital mobile health (mHealth) interventions in youth during the COVID-19 pandemic.

Methods
Data were collected as part of the ‘Mental Health And Innovation During COVID-19 Survey’ -a cross-sectional panel study including a representative sample of individuals aged 16 to 25 years (N=666; M_age 21·3) living in Germany. The study commenced on May 7^th and was completed on May 16^th, 2020.

Results
We found that 57% of youth met criteria for mild to severe psychological distress and 30% felt ‘often’ or ‘very often’ socially isolated. Social isolation, COVID-19-related worries and anxiety, and social risk indicators were associated with psychological distress, with evidence of dose-response relationships for some of these associations. For instance, psychological distress was progressively more likely to occur as levels of social isolation increased (reporting ‘never’ as reference group: ‘occasionally’: adjusted odds ratio [aOR] 9·1, 95% confidence interval [CI] 4·3 - 19·1, p<0·001; ‘often’: aOR 22·2, CI 9·8 -50·2, p<0·001;’ very often’: aOR 42·3, CI 14·1 - 126·8, p<0·001). There was evidence that psychological distress, worries, and anxiety were associated with a positive attitude towards using mHealth tools, whereas high levels of psychological distress, worries, and anxiety were associated with actual use.

Conclusion
Public health measures during pandemics may be associated with poor mental health outcomes in youth. Digital interventions may help mitigate the negative psychosocial impact without risk of viral infection given there is an objective need and subjective demand. Young people use digital tools to manage their mental health at times of public health crises. As the quality of evidence of currently available apps is often unknown or very limited, there is an urgent need to 1) develop and evaluate digital interventions specifically designed to address social isolation and poor mental health during public health crises across the full spectrum of public mental health provision (i.e., mental health promotion, prevention, treatment) and 2) make evidence-based digital interventions publicly available to improve public mental health.