BackgroundEarly COVID-19 research suggests a detrimental impact of the initial lockdown on youngpeople’s mental health, but it is unclear whether the impact would persist.AimsWe investigated mental health symptoms amongst university students after the firstlockdown in the UK and changes in symptoms over 6 months. We examined risk factors forthese symptoms and whether they were shared by young people not in higher education.Method895 university students and 547 young people not in higher education completed an onlinesurvey at T1 (July-September 2020). A subset of 203 university students also completeda 6-month follow-up survey at T2 (January-March 2021). Mental health symptomsmeasured were anxiety, depression, insomnia, substance misuse, and suicide risk.ResultsAt T1, nearly 40% of the participants reported moderate to severe symptoms of anxiety anddepression and risk of substance misuse; a quarter reported insomnia and clinicallysignificant suicidal risk. A reduction in anxiety, depression and insomnia was observed inparticipants reassessed at T2, but not in substance misuse and suicidality.Cross-sectionally, greater symptoms across measures were consistently associated withgender (female or other), sleep irregularity, and a worse-off financial status. Longitudinally,the most consistent risk factors for T2 symptoms were having previously diagnosed mentalhealth problems and having difficulty sleeping since the first lockdown.ConclusionsMental health symptoms were prevalent in a large proportion of young people after the firstlockdown. Risk factors identified may help characterise high-risk groups for enhancedsupport and inform interventions in both university and non-university settings.