23
Dec
Review Links Exposure to Pesticides During Military Service to Negative Mental Health Outcomes
(Beyond Pesticides, December 23, 2025) A literature review of military personnel reveals broad evidence linking their toxic exposure to poorer mental health outcomes. The review, written by medical professionals and researchers throughout the U.S. and published in Medical Care, analyzes the existing literature on associations between military environmental exposures (MEEs) to contaminants, including pesticides, and mental health (MH) 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,†the authors explain.
The 49 studies in the review, covering chemical exposures for military members, involve chemical munitions from the Gulf War era and Agent Orange from the Vietnam War era that are associated with symptoms of depression, PTSD, and anxiety, among others. “Overall, available evidence suggests that veterans reporting environmental toxic exposures may report relatively high levels of mental health needs,†the researchers report.
They continue: “To date, no studies have synthesized the existing literature linking MEEs to MH outcomes. In this review, we systematically organize and describe peer-reviewed literature studying associations between MEEs and MH and neurocognitive outcomes (ie, diagnoses and symptoms). Our review focused on 2 key questions (KQs): for which MEEs has the co-occurrence of psychiatric conditions or symptoms been evaluated (KQ1)? What is the range of prevalence, incidence, or association of co-occurring psychiatric conditions or symptoms among individuals with a history of MEEs (KQ2)?â€
Background
The key questions in the review highlight important areas of concern, particularly the disproportionate risks of exposure for military service members to toxicants that have deleterious health effects. There is a long history connecting U.S. service members to risks from environmental exposures, from burn pits and radioactive materials to toxic biological and chemical agents such as pesticides and chemical weapons. As Beyond Pesticides has previously reported, these exposures can have long-term impacts for veterans, with transgenerational effects that risk the health of their families.
“While some military environmental exposures (MEE; eg, exposure to heat, infectious agents, noise, and chemical solvents) have been experienced across all military eras, other exposures are specific to a service era,†the authors note. They continue: “For instance, Agent Orange is an herbicide used during the Vietnam War, and oil well fires and chemical agents (eg, sarin from the Khamisiyah Munitions Depot demolition) were exposures unique to the wars in the Persian Gulf and Iraq and Afghanistan. Gulf War service has also come to be associated with a wide variety of medically unexplained symptoms affecting cognitive, emotional, and physical functioning. This has come to be known as Gulf War Illness or Chronic Multi-Symptom Illness.â€
Previous Daily News coverage, titled Health Risks Found from Exposure to Agent Orange Residues on Military Aircraft, reports that during the Vietnam War, over 10 million pounds of the toxic herbicide Agent Orange were applied from military aircraft to defoliate forests and destroy civilian crops. Outfitted with spraying equipment, UC-123 transport planes played a major role in the American military’s campaign to eliminate forest cover for Vietcong fighters. After the war, these aircraft were returned to use in the United States for basic transport operations such as cargo shipping and medical evacuation missions.
However, these planes never underwent any form of decontamination or testing before being repurposed for use in the U.S. Although the U.S. Air Force and Department of Veteran Affairs asserted that “dried residues†on these aircraft were not likely to pose a health threat to aircraft crew—a justification used to deny sickened veterans medical support—a study from the journal Environmental Research finds strong evidence of health risks from residual exposure.
Agent Orange was given its name because it was stored in orange-striped drums and contained the active ingredients in the herbicides 2,4-D and 2,4,5-T. Past studies have found that U.S. war veterans exposed to Agent Orange developed chronic lymphocytic leukemia, Hodgkin’s disease and non-Hodgkin lymphoma, prostate cancer, Parkinson’s disease, and diabetes. Many children of exposed veterans have been affected by their parents’ exposure to the chemical and show a wide range of symptoms. (See here and here.)
A Daily News article on Gulf War Illness (GWI) reports on research that establishes strong causal evidence that GWI is the result of exposure to sarin gas, an organophosphate nerve agent used by Saddam Hussein as a chemical weapon during the Gulf War. The findings, published in Environmental Health Perspectives, have important implications for the hundreds of thousands of American service members suffering from a constellation of chronic symptoms without a true understanding of how they became sick. (See additional coverage here.)
Study Importance
As stated in the current literature review, “MEEs have been associated with a wide range of adverse health effects in studies of military service members.†The researchers continue, writing: “Most studies examined the physical or physiological effects of MEEs, and some reported genetic and epigenetic changes associated with MEEs. Specific MEEs have been associated with the development of respiratory diseases, liver and kidney damage, blood disorders, movement disorders, and various types of cancer. While the research on mental health (MH) and cognitive implications of these exposures is more scant, increasing evidence has linked military deployment-related MEEs to adverse mental health and cognitive effects.â€
As a result of increasing attention on the link between military exposure and health post-deployment, the Sergeant First Class Heath Robinson Honoring Our Promise to Address Comprehensive Toxics (PACT) Act was passed in 2022. “The PACT Act expanded Veteran Affairs (VA) health care eligibility for veterans with medical conditions presumed to result from MEEs and mandated MEE screening of all veterans,†the authors say. “To date, over 5 million veterans have been screened, with almost half (43%) reporting at least one MEE.â€
As highlighted in previous Daily News, the PACT Act provides compensation and additional services for exposure to burn pits, as well as contaminated water and Agent Orange. This acknowledges the exposure-related conditions, including but not limited to:
- Cancers of the brain, head, neck, and nervous system
- Brain and nervous system disorders (i.e., Parkinson’s Disease)
- Sarcomas
- Spinal cord cancers
- Gastrointestinal cancers
- Kidney cancers
- Lymphomas
- Melanomas
- Pancreatic cancers
- Reproductive cancers
- Respiratory cancers
- Various non-cancer conditions (High blood pressure/hypertension, chronic obstructive pulmonary disease, pulmonary fibrosis, among others.)
Methodology and Results
Through the literature review process, 49 studies were identified that reference military exposure and mental health symptoms and were included in subsequent analyses. “We organized our results into 3 broad categories, informed by the Diagnostic and Statistical Manual-5-Text Revision (DSM-5-TR) and clinical application,†the researchers state. “These groups included psychiatric diagnoses (eg, posttraumatic stress disorder, PTSD; major depressive disorder, MDD), psychiatric symptoms (eg, low mood and anxiety), as well as neurocognitive diagnoses (eg, major and mild neurocognitive disorder), and neurocognitive symptoms (eg, executive dysfunction and impaired memory).â€
Of the 49 studies, 41 report disaggregated psychiatric or neurocognitive outcomes, “of which 22 studies reported neurocognitive symptoms or diagnostic outcomes, 19 reported psychiatric diagnostic outcomes, and 30 reported psychiatric symptoms (categories not mutually exclusive).†This research includes a range of cohort, case-control, and cross-sectional studies throughout the eras of the “Persian Gulf War (N=29), Vietnam War (N=7), Iran-Iraq War (N=4), Operation Iraqi Freedom (OIF; N=5), Operation Enduring Freedom/Operation New Dawn (OEF/OND; N=3), and other (eg, peacetime, multiera, or not reported, N=5.â€
The results linking MEE to negative mental health outcomes include:
- Depressive Symptoms. Seventeen studies associate depressive symptoms with various military exposures, including chemical weapons, pesticides, and herbicides as the most commonly reported.
- Depressive Disorders. Five studies examine associations between depressive disorders and MEEs, with the most commonly studied exposure including chemical weapons (sulfur mustard and sarin) and the herbicide Agent Orange.
- Anxiety Symptoms. Nine studies find associations between anxiety symptoms and exposures, particularly for herbicides and chemical weapons.
- Anxiety Disorders. Four studies show anxiety disorders in relation to chemical exposures. “This included sulfur mustard gas (Gulf War era), sarin nerve agents (Iran-Iraq War era), and the contaminated water at Camp Lejeune.â€
- Symptoms of Posttraumatic Stress. Nine studies include symptoms of PTSD as an outcome of MEE, with chemical exposures including pesticides, herbicides, solvents, paints, and chemical-based weapons.
- Posttraumatic Stress Disorder (PTSD). Six studies assess the association between PTSD and military exposures, five of which explore chemical weapons exposures (such as sulfur mustard gas and sarin nerve agent).
- Sleep Problems. Seven studies identify sleep problems in relation to MEEs, including chemical weapons and pesticides.
- Sleep Disorders. Two studies assess sleep disorders in relation to chemical exposures, with one study of Agent Orange-exposed Vietnam veterans and the other on veterans who had been exposed to contaminated water at Camp Lejeune.
- Symptoms of Psychosis. Three studies assess symptoms of psychosis, with all participants reporting chemical exposures and two of the studies including Vietnam veterans exposed to Agent Orange.
- Psychotic Disorders. Two studies assess psychotic disorders in Korean veterans and those exposed to Agent Orange in Vietnam.
- Other Psychological Disorders. Eight other studies assess the relationship between toxicants and psychological disorders, including exposure to oil fires, pesticides, and chemical weapons.
The literature review authors report that this collection of studies reveals two main findings: “First, there is broad evidence that toxic exposures during military service are associated with poorer MH. For example, exposure to chemicals and air pollution appears to be associated with a high occurrence of PTSD and posttraumatic stress symptoms. Nevertheless, such findings should be understood within the context of our second broad finding—there are several methodological limitations in the literature examining environmental exposure during military service and MH outcomes, including the imprecise measurement of MEEs and MH symptoms or diagnoses.â€
While there is evidence linking military exposure to negative mental health outcomes, relying on self-reported data, often many years or decades after the exposure occurs, makes it difficult to link the two events. “Despite these limitations, the overall pattern of associations between MEE and MH has important clinical implications,†the researchers conclude. They continue: “Given the broad associations between MEE and MH, it would be useful for clinical care to include screening for symptoms of depression, anxiety, and PTSD among veterans reporting MEEs. Assessing the MH needs of this group may help ensure this higher-risk population receives the neuropsychological and mental health care they need.â€
Forging an Organic Path Forward
The solution to these disproportionate risks for military service members lies in systems-based, holistic change. Whether in the military, commercial agriculture, or home gardens, toxic pesticides and other environmental contaminants have no place. The threats to the health of entire ecosystems, wildlife, and humans are unreasonable, especially given available alternatives such as organic land management.
Learn more about the health and environmental benefits of organic methods here and here. Have your voice heard by participating in Action of the Week, which is intended to provide you, our supporters and network, with one concrete action that you can take each week regarding governmental actions that are harmful to the environment and public and worker health, increase overall pesticide use, or undermine the advancement of organic, sustainable, and regenerative practices and policies.
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All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Magnante, A. et al. (2025) Psychiatric Conditions and Symptoms After Toxic Environmental Exposures During Military Service: An Evidence Map, Medical Care. Available at: https://journals.lww.com/lww-medicalcare/fulltext/2026/01002/psychiatric_conditions_and_symptoms_after_toxic.9.aspx.
