Psychiatric Conditions and Symptoms After Toxic Environmental Exposures During Military Service: An Evidence Map

US service members are often exposed to a range of service-related hazards. To date, there has been limited synthesis of the existing research conducted on military environmental exposures and subsequent psychiatric conditions and symptoms.

To systematically review and characterize the main features of studies examining associations between military exposures and mental health outcomes.

We used evidence mapping methodology to systematically search MEDLINE, Embase, PsycINFO, and PTSDpubs for studies of toxic exposure during military service and psychiatric outcomes, which included psychiatric diagnoses, psychiatric symptoms, and neurocognitive functioning.

We identified 49 studies; most were comprised of predominantly White, male veteran samples. Chemical exposures, including chemical munitions from the Gulf War era and Agent Orange from the Vietnam War era, were the most frequently examined military toxic exposures. Symptoms of depression, PTSD, and anxiety were the most commonly examined psychiatric outcomes. Only 9 studies assessed neurocognitive functioning. We found extensive variation in how exposures and outcomes were defined and measured. Most exposure and symptom data were based on self-reports. Overall, available evidence suggests that veterans reporting environmental toxic exposures may report relatively high levels of mental health needs.

We found broad evidence that toxic exposure was associated with poorer mental health outcomes, though the ability to draw stronger conclusions is limited by the quality of the current literature. Future research should focus on longitudinal studies of toxic exposure and mental health that include more broadly representative military populations, including diverse samples and more recent service cohorts.