BackgroundWe aimed to assess the prevalence of depressive and anxiety symptoms, hopelessness and insomnia in the older adults before and during the COVID-19 pandemic identifying subgroups at higher risk of mental distress. MethodsWithin the Lost in Lombardy project, a web-based cross-sectional study was conducted on a representative sample of 4400 older adults aged 65 years or more from the Lombardy region recruited between November 17th and 30th 2020. ResultsThe prevalence of depressive symptoms increased by +112 % during the pandemic, anxiety symptoms by +136 %, insufficient sleep by +12 %, unsatisfactory sleep by +15 %. Feelings of hopelessness were more frequent among women compared to men and increased with increasing age. A worsening in each of the four specific mental health outcomes was more frequently observed in women (OR = 1.50, depression; OR = 1.31, anxiety; OR = 1.57, sleep quality; OR = 1.38, sleep quantity), in subjects who decreased their physical activity during the pandemic (OR = 1.64, depression; OR = 1.48, anxiety; OR = 2.05, sleep quality; OR = 1.28, sleep quantity), and with increasing number of pre-existing chronic diseases. The use of at least one psychotropic drug – mostly antidepressants/anxiolytics – increased by +26 % compared to pre-pandemic. LimitationsPre-pandemic symptoms were retrospectively reported during the Covid pandemic. Potential information and recall bias should not be ruled out. ConclusionsIf confirmed by future longitudinal studies, our findings could support evidence-based health and welfare policies on responding to this pandemic and on how to promote mental health and wellbeing, should future waves of infection emerge.