A Longitudinal Study of Psychosocial and Behavioral Adaptations to Continuous Community Violence in Culiacán, Sinaloa, México.

This study examined how residents of Culiacán, México, adapted over time to prolonged community violence and perceived insecurity. We evaluated a two-speed adaptation theory, which proposes that indicators of acute psychological distress and economic strain decline over time, whereas protective behavioral responses persist as a state of chronic vigilance. A mixed-longitudinal design was employed, consisting of a baseline survey of 1163 residents conducted in October 2024 and a longitudinal cohort of 100 participants followed in February and June 2025. Longitudinal changes were evaluated using Cochran's Q tests with exact McNemar post hoc comparisons, proportions were reported with 95% Clopper-Pearson confidence intervals, and multivariable logistic regression was used to examine predictors of migration intent. Pharmacologic treatment utilization declined significantly from 36% to 20%, and reported economic strain decreased from 62% to 35% over the study period. In contrast, behavioral routine modifications remained persistently high, decreasing only from 95% to 88%, with no statistically significant longitudinal change. These findings are consistent with the proposed theory, suggesting that while acute psychosocial and economic impacts may diminish over time, protective behavioral adaptations remain comparatively stable. Regarding migration intent, individual economic strain was not significantly associated with the intention to leave the city. Instead, participants who attributed insecurity primarily to social contract collapse, conceptualized as the perceived erosion of community trust, institutional legitimacy, social polarization, and the breakdown of social order, had substantially greater odds of reporting migration intent than those primarily concerned with economic factors (OR = 11.56, 95% CI 1.55-85.98). Overall, these findings suggest that prolonged community violence produces distinct trajectories of psychosocial adaptation, in which acute distress decreases while chronic vigilance persists. Furthermore, migration intentions appear to be more strongly associated with perceived deterioration of the social environment than with individual economic hardship, highlighting the importance of restoring community trust and institutional legitimacy alongside traditional public health and economic interventions.