Heterogeneous trajectories of psychological distress among individuals with moderate or severe distress: A five-year...

While trajectory research has advanced understanding of population-wide psychological distress patterns, heterogeneity among already-distressed individuals remains largely overlooked. This study aimed to classify five-year trajectories among individuals with moderate and severe distress, and to identify psychosocial factors related to more symptomatic trajectories.

Using a nationwide cohort data (2020-2024), latent class growth analysis was employed to identify distinct trajectories within moderate (K6 5-12; n = 6243) and severe (K6 ≥ 13; n = 2346) distress groups. Multinomial logistic regression examined predictors of trajectory membership with multiple imputation.

Three trajectories emerged for those with moderate baseline distress: recovery (51.5%), persistently moderate (41.6%), and progressively severe (6.9%). Among those with severe baseline distress, four trajectories were identified: recovery (43.4%), improved but moderate (27.2%), improved but severe (17.9%), and persistently severe (11.5%). In both groups, a substantial proportion showed recovery within the first year; however, those who did not recover by the following year tended to remain distressed throughout. Most demographic characteristics and health behaviors showed inconsistent or null associations across groups. Adverse childhood experiences demonstrated a consistent dose-response association with more symptomatic trajectories. Loneliness and psychiatric history also strongly predicted higher-risk trajectories.

Among individuals with psychological distress, early recovery within one year might be an important indicator of subsequent trajectory: those who do not show improvement by the following year are at substantially elevated risk of persistent burden. These findings support the importance of secondary prevention efforts targeting already-affected individuals, particularly those with early-life adversity and current psychosocial risks.