How can sleep disorders affect our reaction towards external stressors: a lesson from the COVID-19 outbreak.

Background: The COVID-19 outbreak produced extensive psychological consequences, especially among vulnerable populations. Sleep was identified as one of the most common "indirect targets" of the pandemia, with up to 74.8% of patients surviving from COVID-19 complaining of new-onset sleep disorders. However, so far, the clinic-psychological impact of the outbreak in patients affected by pre-existing sleep disorders has not been examined in details.

Materials And Methods: In the present study, we aim to assess the effect of the COVID-19 outbreak in a cohort of 190 adult patients affected by sleep disorders, compared to 265 age and sex-matched healthy sleepers. The assessment was implemented throughout the use of ad hoc anamnestic questions, exploration of dream content, and validated questionnaires, aiming to capture the broad range of the neuropsychological nuances of the COVID-19 impact.

Results: Subjects with pre-existent sleep disorders faced a more severe impact in terms of sleep quality and amount compared to healthy sleepers, presenting longer sleep latency, reduced sleep efficacy, and greater use of hypnotics and medications. On the other hand, healthy sleepers experienced deeper variation in sleeping habits, sleep duration, and greater impact on dream activity in terms of content, emotionality, and presence of recurrent dreams. Finally, in our sample, being female represents an important aggravating factor in the pandemic experience, both in terms of sleep deterioration and with respect to physical and mental health. For instance, females indeed presented the highest scores of Pittsburgh Sleep Quality Index (PSQI) both in cases and control groups (respectively 10 ± 3.8 vs 7.3 ± 3.9 in cases and 6.6 ± 3.6 vs 6.0 ± 3.4 in controls, p-value < 0.001).

Conclusion: Pre-existent sleep disorders and the female sex might represent risk factors increasing the clinic-psychological burden in dramatic scenarios, such as the COVID-19 pandemia, requiring dedicated attention from clinicians.