Predictors of Posttraumatic Stress Symptom Trajectories Following the Fatal 2011 Christchurch, New Zealand Earthquake.

People respond differently to potentially traumatic events. To explore predictors of a chronic and delayed trajectory of posttraumatic stress symptoms (PTSS) after a natural disaster, we analyzed psychometric data collected from 412 residents of Christchurch, New Zealand after a 6.3 magnitude earthquake struck in February 2011. Participants from suburbs with different levels of socioeconomic status (SES) and earthquake impact completed a door-to-door survey 4-7 months after the earthquake (Time 1; N = 600) and again 10-11 months after the earthquake (Time 2; N = 412). The survey included the Acute Stress Disorder Scale, the Patient Health Questionnaire's nine-item Depression subscale, and the Generalized Anxiety Disorder-7 scale, along with single-item measures of variables including aftershock anxiety and family tension. Hobfoll's conservation of resources theory was used to guide data interpretation. High levels of depression, odds ratio (OR) = 1.24, and anxiety, OR = 1.24, at Time 1 significantly predicted membership in the chronic trajectory. Predictors of a delayed onset of symptoms included increased aftershock anxiety, OR = 1.29, and family tension, OR = 1.35, over time, as well as living in an area defined as being of low, OR = 5.36, or medium, OR = 11.39, SES. Results highlight risk factors for elevated PTSS and resources that individuals can use to offset threatened loss. These findings have implications for service providers, agencies, and the public.