Fig. 1From: A PTSD symptoms trajectory mediates between exposure levels and emotional support in police responders to 9/11: a growth curve analysisSelf-reported retrospective exposure levels (0–5), measured at Wave 1, remain continuously related to PTSD symptom levels across three waves of data collection, 2003–2011. Note. N = 2,197. Stress response measured by the PCL checklist of PTSD symptoms [20]. Quadratic interaction between time and exposure (p = .006)Back to article page