Looking for resilience: Understanding the longitudinal trajectories of responses to stress

Taking advantage of two large, population-based, and longitudinal datasets collected after the 1999 floods in Mexico (n = 561) and the September 11, 2001 terrorist attacks in New York (n = 1267), we examined the notion that resilience may be best understood and measured as one member of a set of trajectories that may follow exposure to trauma or severe stress. We hypothesized that resistance, resilience, recovery, relapsing/remitting, delayed dysfunction, and chronic dysfunction trajectories were all possible in the aftermath of major disasters. Semi-parametric group-based modeling yielded the strongest evidence for resistance (no or mild and stable symptoms), resilience (initially moderate or severe symptoms followed by a sharp decrease), recovery (initially moderate or severe symptoms followed by a gradual decrease), and chronic dysfunction (moderate or severe and stable symptoms), as these trajectories were prevalent in both samples. Neither Mexico nor New York showed a relapsing/remitting trajectory, and only New York showed a delayed dysfunction trajectory. Understanding patterns of psychological distress over time may present opportunities for interventions that aim to increase resilience, and decrease more adverse trajectories, after mass traumatic events. (C) 2009 Elsevier Ltd. All rights reserved.