Insomnia and related factors in patients with pre-existing psychiatric disorders compared to the general population during the COVID-19 lockdown: Findings from the multicentric COMET study

Background: The COVID-19 pandemic has heavily impacted social, economic and health systems worldwide. Necessary confinement measures have, in turn, contributed to the occurrence of several stress-related conditions and deterioration of pre-existing mental conditions, including insomnia. Objective: The present study sought to investigate the occurrence and severity of insomnia during the COVID-19 lockdown among psychiatric patients and in the general population in the largest Italian sample examined to date. Potential factors associated with a risk of developing insomnia in the global sample were examined as well. Methods: A sample of 20,720 people (5.5% of them being psychiatric patients) was assessed through an online survey conducted during lockdown between March and May 2020. To investigate the occurrence and severity of sleep related issues, the Insomnia Severity Index (ISI) was used. In order to evaluate factors associated with the severity of insomnia in the global sample, multivariate linear regression models were performed. Results: During the lockdown, patients with pre-existing mental disorders reported a mean higher score on the ISI scale (p < 0.001) compared to the general population. According to the multivariate regression models, the first three weeks of lockdown were significantly associated with a higher risk of insomnia, but the risk disappeared in the fourth week. Other associated factors included: the presence of a pre-existing mental disorder, ages 24 to 64 years old, and/or being female (p < 0.001). Conclusions: Although containment measures represent essential public health strategies to avoid the spread of the COVID-19 pandemic, sleep was one of the aspects affected during the early stages of the lockdown in both people with pre-existing mental disorders and general population. As an integral part of COVID-19 intervention, it is useful to raise awareness about these issues and to adopt both preventive and therapeutic interventions.