This document is a summary of a special issue of the journal Brain Sciences that focuses on the effects of the COVID-19 pandemic on sleep and dream activity. The collection of articles examines various populations, including adolescents, elderly individuals, children with autism spectrum disorder or attention deficit hyperactivity disorder, individuals with chronic diseases, and the general population. The studies highlight the negative impact of the pandemic on sleep quality, insomnia symptoms, pre-sleep arousal, and sleep efficiency. The results also indicate that the effects of the pandemic on sleep vary depending on factors such as age, pre-existing health conditions, and specific diagnoses. The findings emphasize the need for tailored treatment strategies to address the sleep and mental health problems caused by the pandemic. [Extracted from the article]