Coronavirus disease 2019 (COVID-19) is a global pandemic . Measures to reduce transmission of the virus have altered usual activities, routines, and livelihoods, and have had a significant impact on mental health . The current study aims to examine the potential alterations in psychological wellbeing, mental health, sleep and diurnal preference due to the COVID-19 pandemic . A cross sectional online questionnaire-based study with n = 200 participants (aged 18-62; 7.86.0% female , 93.0% white , 92.5% UK-based , 73.5% students). Data were collected between 15th April and 8 June 2020 . Participants answered questions on lifestyle changes and their concerns and worries about COVID-19, and completed the SCI, PHQ9, GAD7, PWB18, UCLA3 and MEQ . Results showed self-isolation was linked to lower psychological well-being, and increased loneliness, anxiety and depression . Home-working was related to a shift in diurnal preference . Reduced work/income was related to decreased psychological well-being and sleep quality and increased anxiety, depression, loneliness and . Intensity of worried thoughts and concerns about COVID-19 were positively correlated with anxiety, depression and negatively with sleep quality . In conclusion, the social, occupational and economic disruption due to COVID19 has had a negative impact on psychological well-being . However, the transition to home-working may have been somewhat beneficial for some individuals in terms of sleep . These findings should be taken into account by policy makers during the transition to the 'new normal' post-pandemic.