Analysis of the correlations between insomnia and mental health during the COVID-19 pandemic in Germany

OBJECTIVE: This study evaluates correlations between insomnia and mental health during the COVID-19 pandemic in Germany. METHODS: The internet-based International COVID-19 Sleep Study (ICOSS) questionnaire including sociodemographic questions as well as sleep- and emotion-related scales was distributed in Germany during the COVID-19 pandemic from May 1 to September 30, 2020. Insomnia and mental state were assessed using the Insomnia Severity Index (ISI), Patient Health Questionnaire (PHQ), Generalized Anxiety Disorder (GAD-2), and visual analogue scale. Qualitative analyses of demographic characteristics were performed and correlation analyses of the variables calculated. RESULTS: A total of 1103 individuals participated and 858 valid questionnaires (70.61% females) were obtained. Mean age and body mass index were 41.97 ± 12.9 years and 26 ± 5.9 kg/m(2), respectively. Most participants were married (n = 486, 56.6%), living in the city (n = 646, 75.3%), and white (n = 442, 51.5%). The prevalence of insomnia, anxiety, and depression was 19.5% (ISI > 7), 6.6% (GAD-2 > 3), and 4.8% (PHQ-2 > 3), respectively. Compared to the insomnia group, the mean and median ISI, PHQ‑4, PHQ‑2, and GAD‑2 scores of the non-insomnia group were lower, while their mean and median quality of life and quality of health scores were significantly higher (P < 0.05). Pearson correlation analysis showed a positive correlation between the ISI and PHQ‑2 (r = 0.521, P < 0.001), GAD‑2 (r = 0.483, P < 0.001), and PHQ‑4 scores (r = 0.562, P < 0.001); however, the ISI score negatively correlated with the quality of life (r = −0.490, P < 0.001) and quality of health scores (r = −0.437, P < 0.001). CONCLUSION: Insomnia, anxiety, and depression were very prevalent during the pandemic. Anxiety and depression were more severe in the insomnia than in the non-insomnia group, and insomnia and mental health are closely related.