Since 2020, modern youth in Ukraine have faced an exceptionally challenging period, first enduring the burdens of the COVID-19 pandemic and then being thrust into the full-scale war, characterized by persistent traumatic exposure. Given the profound and lasting psychological consequences of such crises, it is essential to monitor the long-term impact of war on youth mental health. However, despite the urgency of this issue, longitudinal studies with large, diverse samples remain scarce. This study aims to track changes in anxiety, depression, and stress and explore their associations with demographic and educational variables among university students in Ukraine, from the COVID-19 pandemic through two years of full-scale war. Data were collected online at three time points over four years from independent samples of students from 27 higher education institutions across 12 Ukrainian cities. A total of 757 students participated in 2020, 2,592 in 2023, and 838 in 2024, all completing anonymous questionnaires. A one-way analysis of variance (ANOVA) and a General Linear Model were used to analyse the results. The findings revealed a significant increase in anxiety, depression, and stress levels among university students during the transition from the pandemic to wartime conditions. Women reported higher levels of anxiety, depression, and stress, while students aged 15-25 exhibited poorer mental health than those aged 26-55. Although students across all fields of study experienced heightened distress in 2023, those in technical disciplines were the only group to show a decline in 2024. Ukrainian youth have been living under high levels of distress for more than four years, with little indication of improvement. The results highlight the urgent need for targeted strategies in prevention, intervention, and treatment of anxiety, depression, and stress among university students and other vulnerable young adults.