An outbreak in Wuhan, China in late 2019 of a highly infectious new coronary pneumonia (COVID-19) led to the imposition of countrywide confinement measures from January to March 2020. This is a longitudinal study on changes in the mental health status of a college population before and after their COVID-19 confinement for the first two weeks, focusing on states of psychological distress, depression, anxiety and affectivity. The influence of possible stressors on their mental health were investigated, including inadequate supplies and fears of infection. Five hundred and fifty-five undergraduate students were recruited from Hebei Agricultural University in Baoding, China. The participants completed two online surveys—on anxiety and depression, and on positive and negative affect. One survey was conducted before the confinement and the other was conducted 15–17 days after the start of the confinement. Increases in negative affect and symptoms of anxiety and depression (p-values < 0.001) were observed after 2 weeks of confinement. Inadequate supplies of hand sanitizers, a higher year of study, and higher scores on anxiety and depression were common predictors of increased negative affect, anxiety, and depression across the confinement period. The results suggest that healthcare policymakers should carefully consider the appropriate confinement duration, and ensure adequate supplies of basic infection-control materials.

Accurate self-assessment of Big Five personality traits in middle childhood remains challenging. To address this gap, this study developed and validated the Chinese Pictorial Big Five Personality Inventory for Children (CPBFI-C), a novel self-report tool designed for children as young as 6 years old. The CPBFI-C was developed based on the facet-informed structure of the Big Five Inventory-2, with items sampled to represent diverse facet content within each domain and combined with pictorial stimuli tailored to Chinese cultural contexts to enhance comprehension and engagement. In Study 1, based on a sample of 2,484 primary school students (Sample 1, aged 6–14), the CPBFI-C demonstrated acceptable internal consistency, good test–retest reliability, and excellent structural validity via exploratory structural equation modeling. Crucially, the scale achieved strict measurement invariance across age groups (6–9 vs. 10–14 years) and partial strict invariance across sex. Furthermore, partial scalar invariance was established between the picture-based version and the text-only version administered to Sample 2, which comprised 2,282 students in Grades 4–7. The alignment method was employed for sex and test format and confirmed approximate measurement invariance, thus allowing for meaningful group comparisons. These results support the scale's robust psychometric properties across diverse demographics and formats. In Study 2, utilizing three independent subsamples for external validation, the CPBFI-C showed statistically significant and meaningful self–other agreement with parent-reported personality. Furthermore, it exhibited strong external validity through theoretically consistent correlations with children's self-reported depressive symptoms and teacher-evaluated academic performance. Alignment-with-covariates analysis further showed broadly comparable associations across sex groups. In summary, the CPBFI-C is a reliable, valid, and engaging instrument, and provides researchers with an effective Big Five self-assessment tool for measuring children as young as 6 years old.