A systematic review of pre-pandemic resilience factors and mental health outcomes in adolescents and young adults during the COVID-19 pandemic.

Adolescence and young adulthood are sensitive developmental periods to environmental influences. Investigating pre-emptive measures against stressors, such as those associated with the COVID-19 pandemic, on mental health is crucial. We aimed to synthesize evidence on pre-pandemic resilience factors shaping youth mental health outcomes during this period. For this pre-registered systematic review, we searched seven databases for longitudinal studies of youth populations affected by the COVID-19 pandemic, assessing a priori defined resilience factors at the individual, family, or community level before the pandemic. Studies required validated mental health or wellbeing measures collected both before and during the pandemic. Study quality was assessed using the corresponding NIH Quality Assessment Tool. From 4,419 unique records, 32 studies across 12 countries were included, using 46 distinct resilience measures. Due to the heterogeneity of study designs, we applied a narrative synthesis approach, finding that resilience factors were generally associated with better mental health outcomes both prior to and during the pandemic. However, most factors did not mitigate pandemic-related mental health effects. Nonetheless, family-level resilience factors emerged as promising under specific conditions. Study quality was generally fair, with concerns in resilience assessment and sampling quality. Future research should prioritize rigorous study designs and comprehensive resilience assessments.