Exploring psychological changes of parents during different phases of COVID-19: A cross-sectional study using factor analysis and k-means clustering

• Novel multi-time latent profiling method combining EFA and k-means clustering. • Five parental mental health phenotypes identified: optimist to depressed. • U-shaped temporal trajectories show post-lockdown psychological recovery lag. • Mothers & young parents exhibit heightened volatility across pandemic phases. The COVID-19 pandemic has exposed critical gaps in mental health support systems for vulnerable populations. While prior studies have documented parental stress during acute pandemic phases, longitudinal patterns across pandemic stages remain unexplored. This large-scale study examines the trajectory of parental mental health in China through three distinct pandemic phases (containment, normalization, reopening), addressing the critical need for time-sensitive intervention strategies. A total of 166,435 parents (81.9 % mothers) were administered self-assessment questionnaires concerning both the pandemic and their mental well-being, during three phases: initial outbreak (April 2020), sustained control (November 2020) and policy relaxation (November 2021). Exploratory factor analysis extracted six latent dimensions, which accounted for 44.8 % of the total variance. K-means clustering ( k = 5 determined by elbow method) categorized participants into mental health profiles. Subsequently, changes in the proportions of different clusters across different time points were investigated. Mental health trajectories followed a U-shaped curve: the proportion of parents identified as optimists decreasing from 33.6 % during the initial lockdown to 23.2 % at the pandemic peak, followed by a rebound to 43.8 % in the post-restriction phase. Latent transition analysis revealed significantly higher volatility in mental health trajectories among younger parents (<30 years). Additionally, mothers reported higher levels of psychological distress compared to fathers. Findings reveal parents’ complex emotional challenges during the pandemic, stressing the need for tailored support, especially for mothers. By emphasizing age and gender, the research deepens understanding of COVID-19′s psychological impacts and calls for refined mental health approaches in global crises.