A study shows that during the first confinement, day-to-day variations in subjective sleep quality influenced the occurrence of mental and physical health complaints, and that these effects were linked to daily reports of COVID-19 related deaths. The team of researchers led by Peter Simor, CRCN -Center for Research in Cognition and Neurosciences and UNI, ULB Neurosciences Institute, Université libre de Bruxelles (ULB), interviewed 166 participants in three European countries, twice a day for two consecutive weeks via an online interface about their sleep quality and negative psychological experiences.