Network modeling has been applied in a range of trauma-exposed samples, yet results are limited by an over reliance on cross-sectional data. The current analyses used posttraumatic stress disorder (PTSD) symptom data collected over a 5-year period to estimate a more robust between-subject network and an associated symptom change network.

A PTSD symptom network is measured in a sample of military veterans across four time points (Ns = 1254, 1231, 1106, 925). The repeated measures permit isolating between-subject associations by limiting the effects of within-subject variability. The result is a highly reliable PTSD symptom network. A symptom slope network depicting covariation of symptom change over time is also estimated.

Negative trauma-related emotions had particularly strong associations with the network. Trauma-related amnesia, sleep disturbance, and self-destructive behavior had weaker overall associations with other PTSD symptoms.

PTSD's network structure appears stable over time. There is no single ‘most important’ node or node cluster. The relevance of self-destructive behavior, sleep disturbance, and trauma-related amnesia to the PTSD construct may deserve additional consideration.

Firefighters represent an important population for understanding the consequences of exposure to potentially traumatic stressors.

The researchers were interested in the effects of pre-employment disaster exposure on firefighter recruits’ depression and posttraumatic stress disorder (PTSD) symptoms during the first three years of fire service and hypothesized that: (1) disaster-exposed firefighters would have greater depression and PTSD symptoms than non-exposed overall; and (2) depression and PTSD symptoms would worsen over years in fire service in exposed firefighters, but not in their unexposed counterparts.

In a baseline interview, 35 male firefighter recruits from seven US cities reported lifetime exposure to natural disaster. These disaster-exposed male firefighter recruits were matched on age, city, and education with non-exposed recruits.

A generalized linear mixed model revealed a significant exposure×time interaction (ecoef =1.04; P<.001), such that depression symptoms increased with time for those with pre-employment disaster exposure only. This pattern persisted after controlling for social support from colleagues (ecoefficient=1.05; P<.001), social support from families (ecoefficient=1.04; P=.001), and on-the-job trauma exposure (coefficient=0.06; ecoefficient=1.11; P<.001). Posttraumatic stress disorder symptoms did not vary significantly between exposure groups at baseline (P=.61).

Depression symptoms increased with time for those with pre-employment disaster exposure only, even after controlling for social support. Posttraumatic stress disorder symptoms did not vary between exposure groups.

PenningtonML, CarpenterTP, SynettSJ, TorresVA, TeagueJ, MorissetteSB, KnightJ, KamholzBW, KeaneTM, ZimeringRT, GulliverSB. The Influence of Exposure to Natural Disasters on Depression and PTSD Symptoms among Firefighters. Prehosp Disaster Med. 2018;33(1):102–108.