3052 — Selective Effects of Combat Exposure on the Development of Depression and PTSD in OEF/OIF Veterans

Kline A (VA New Jersey Health Care System), Ciccone D (University of Medicine and Dentistry of New Jersey), Losonczy M (New Jersey Health Care System), Sussner B (New Jersey Health Care System)

Objectives:
Although depression is a frequent comorbid condition affecting combat veterans with PTSD, there is disagreement as to whether depressive symptoms constitute a distinctive disorder or an additional manifestation of the spectrum of trauma symptoms. Few studies examining this question, however, have explored the etiological factors associated with each disorder. This study examines relationships between PTSD, depression and combat exposure to determine if differences exist in the types of combat experiences associated with the development of each disorder.

Methods:
Data for this study were collected on 641 New Jersey National Guard OEF/OIF veterans through an anonymous self-administered survey. The PTSD Checklist (PCL-17) and the Patient Health Questionnaire (PHQ) were used to diagnose PTSD and depression, respectively. In addition, patients reported combat experiences during previous OEF/OIF deployments on a validated 21-item combat exposure scale. The scale items were categorized into seven exposure types: 1) being fired on by the enemy, 2) being physically harmed, 3) aggression toward enemy combatants, 4) causing death of non-combatants or fellow soldiers, 5) witnessing dead/injured enemy, 6) witnessing dead/injured Americans, and 7) being in dangerous situations (IED sweeps/house clearing).

Results:
Bivariate correlations between combat exposure types, PTSD and depression revealed PTSD to be correlated with every type of combat exposure except dangerous situations. Depression, however, correlated only with being physically harmed (p = .003), witnessing dead/injured Americans (p = .022), and causing the death of non-combatants (p = 000). In logistic regression analyses, controlling for demographic characteristics, previous mental disorders and non-combat stressors, general combat exposure significantly predicted PTSD (OR = 4.05; p = .000), but was less predictive of depression (OR = 2.16; p = .099). While six of the seven combat experiences predicted PTSD after adjusting for other confounding variables, depression was predicted only by causing the death of noncombatants (OR = 3.30; p = .005) and witnessing dead/injured Americans (OR = 3.29; p = .031).

Implications:
While PTSD is broadly associated with combat trauma, depression is linked to a distinct set of combat situations, suggesting it may represent an autonomous disorder.

Impacts:
Understanding the etiology of depression in combat veterans has important implications for developing effective treatment.