Investigating the relationship between COVID-19-related and distress and ICD-11 adjustment disorder: two cross-sectional studies

Background To assess the prevalence of elevated risk of serious mental illness and probable ICD-11 adjustment disorder in the UK population at two time points during COVID-19, and their association with COVID-19-related stressful events. Aims To check the dose–response model for stress between the number of COVID-19-related stressful events and mental health indices. Method We conducted two cross-sectional studies, using internet survey samples across the UK (N = 1293 for study 1; N = 1073 for study 2). Samples used internet panel surveys during March–April 2020 and 3 months later (June 2020), and used random stratified samples. Studies assessed prevalence of serious risk of mental illness and probable ICD-11 adjustment disorder. Results Elevated risk of serious mental illness was found among those with COVID-19-related social life or occupationally stressful events (study 1). Elevated risk of serious mental illness and probable ICD-11 adjustment disorder was evident among those reporting COVID-19-related stressful events (personal health problems and caregiving; study 2). Cumulative COVID-19-related stressful events were associated with elevated risk of serious mental illness in study 1 (odds ratio 1.65; 95% CI 1.03–2.64; P = 0.037), and with both elevated risk of serious mental illness (odds ratio 2.19; 95% CI 1.15–4.15; P = 0.017) and probable ICD-11 adjustment disorder (odds ratio 2.45; 95% CI 1.27–4.72; P = 0.007) in study 2. Conclusions Psychiatrists should be aware that COVID-19-related stressful events can lead to serious psychological problems. Mental health professionals need to pay particular attention to patients who report cumulative COVID-19-related stressful events, and consider them for mental health assessment and treatment.