(Beyond Pesticides, January 17, 2024) Science continues to find a link between mental health and occupational (work-related) chemical exposure, with a study published in Toxicology finding an increased risk of depression among farmers exposed to pesticides. Conventional, chemical-intensive farming is a profession notorious for higher-than-average pesticide exposure occurrences, thus explaining why the study concludes that individuals within this occupation can suffer from chemically induced oxidative stress, inflammation, and lower education-based cognition that exacerbate depressive symptoms. However, besides psychological symptoms, the study indicates potential physiological issues from pesticide exposure, such as renal (kidney) and hepatic (liver) issues. Studies like this one can directly pinpoint risks of developing depression, especially among agricultural workers and landscapers who use pesticides.
Usually, research on pesticide-induced diseases commonly investigates pesticide exposure concerning the development of various physicalÂ illnesses. However, previousÂ studiesÂ show that occupational risks of developing depression are high in agriculture, where pesticide use is rampant. Acute exposure to chemicals, including organophosphate, organochlorine, triazine, and carbamate pesticides, tends to put farmers atÂ greater riskÂ of suicide than the general population. There is a lack of information connecting pesticide exposure to the subsequent psychological (psychiatric) effects on the general population.
Although the etiology of depressionâ€”and many other psychiatric disordersâ€”is often genetic, studies suggest that other etiological factors, like pesticide exposure, play a role in depression incidents. Poor mental health has aÂ tangibleÂ influence on physical health (e.g., depression and cardiovascular disease); therefore, the combination of pesticide exposure and mental illness worsens the adverse effects on human health. Since pesticide exposure can exacerbate psychiatric symptoms, it is essential to evaluate how pesticide exposure affects mental health in addition to physical health. This research highlights the significance of researching potential mental health detriments resulting from pesticide exposure, especially as society tends to rank mental health risks second to physical health.Â
The study notes, â€ś…[T]he impact of occupational pesticide exposure on the mental health of rural workersâ€¦ [the] underuse of PPEs [personal protective equipment] and the link between depressive symptoms, inflammation, and oxidative stress underscore the urgent need for improved safety measures in agricultural practices. Addressing these issues will contribute to a deeper understanding of the intricate relationship between environmental exposures and mental health outcomes.â€ť
The study assesses the oxidative and inflammatory profiles and mental health of Brazilian farmers exposed to pesticides and compares the results to the control group lacking occupational exposure to pesticides. Researchers gathered data on sociodemographic factors (i.e., age, race, ethnicity, language, economic status), work history, and medical records. Using the State-Trait Anxiety Inventory (STAI) and Beck Depression Inventory (BDI), the researchers evaluate emotional states to determine mental health status. Researchers collected blood samples from the participants to measure redox (oxidative) and inflammatory profiles. The physiological results identify that BDI scores are higher among the pesticide-exposed group (farmers), with these individuals experiencing more severe cases of depression. Physically, the same farmers have increased lipid peroxidation and superoxide dismutase activity, among other oxidative stress markers, and elevated levels of inflammatory signaling cells (cytokines) indicating inflammation. The study notes that the herbicide glyphosate is the most commonly used pesticide among farmers, which may play a role in elevating the enzyme levels in the liver and kidneys of pesticide-exposed participants. Additionally, the results highlight a particularly stark issue concerning the underuse of PPE among farmers and the disparity in education among farmers. Education is pivotal in fostering safety practices, comprehending technical information about pesticide handling, and using PPE.
Within the past two and a half decades, research concerning pesticide exposure and psychiatric disorders, such as depression, has grown, especially for farmworkers. Exposure to agricultural pesticides puts farmers atÂ a six times greater riskÂ of exhibiting depressive symptoms, including chronic anxiety, irritability, restlessness, and sadness. For instance, exposure toÂ organochlorinesÂ andÂ fumigantsÂ (highly toxic, gaseous pesticides) heighten an individualâ€™s risk of depression byÂ 90% and 80%, respectively. Linear modelsÂ reveal an association between lifelong pesticide poisoning episodes and the increased risk of developing mental disorders among tobacco farmers, with farmers using organophosphateÂ pesticides (notorious for neurotoxicity) having a higher prevalence of minor psychiatric disorders. Although individuals suffering from occupational pesticide exposure face a disproportionate risk of developing depression, pesticide exposure from nearby agricultural fields remains a threat to residential (nonoccupational) human health.Â Previous studiesÂ find that populations living near farms are more likely to have high depressive symptoms. Similarly, aÂ 2019 studyÂ found that teens and adolescents living in agricultural areas, where organophosphate exposure is prevalent, are at higher risk of depression. Uniquely, gender (female), physical health, and age (young adult) indicate the likelihood of having depressive symptoms, with the most adverse effects on women, those in poor physical health, and children under 14.Â Regardless of pesticide exposure frequency, duration, intensity, type, and location, the development of depression symptoms remains of concern.
The study highlights the interplay of multiple factors contributing to the prevalence of depression among pesticide-exposed farmers. Despite the study location being in Brazil, the results have implications for farmers across the globe, especially in regions where pesticide policies and practices do little to protect workers. Understanding the mental health implications of conventional pesticide exposure can help identify the various physiological mechanisms attributed to psychiatric disorders. Notably, this study calls for the continued investigation of pesticide neurotoxicity mechanisms and the association between mental health disorders. This and other studies indicate that farmers and those in agricultural communities are at disproportional risk of mental health problems due to pesticide use. Therefore, the study advocates â€śfor comprehensive strategies to improve the mental and physical well-being of rural workers exposed to pesticides, including education, preventive measures, and ongoing research efforts to safeguard the health of those who play a vital role in our agricultural communities.â€ť
Mental health is just asâ€”if not moreâ€“important than physical health, and reviews such as this highlight the importance of knowing pesticide implications beyond physical ailments. According to theÂ World Health Organization (WHO), depression affects 322 million people globally, with the number of diagnosed patients increasing by 18.4% from 2005 to 2015. Annually, onlyÂ halfÂ of Americans with a depression diagnosis seek treatment for symptoms. Untreated symptoms of depression can increase the risk of suicide, a severe sign of depression. Commonalities between occupational and household pesticide exposure are suicidal thoughts and pesticide provocation as a suicide agent. WHO scientists recognize pesticideÂ self-poisoningÂ as one of the most significant global methods of suicide, as increases in pesticide toxicity make them potentially lethal substances.Â
Beyond Pesticides tracks the most recent news and studies related to pesticide exposure through our Daily News (DN) Blog andÂ Pesticide Induced Diseases Database (PIDD). For more information on the multiple harms of pesticides, see our DNs on Pesticides and Depression and PIDD pages onÂ brain and nervous system disorders,Â endocrine disruption, and other diseases.Â Additionally,Â buying,Â growing, and supporting organic can help eliminate the extensive use of pesticides in the environment. It also reduces demand for toxic pesticides in areas where farmer suicides are alarmingly high. Coupled with evidence from past studies that link pesticide exposure toÂ suicidal ideationsÂ andÂ depression, even in developed countries, this research strongly supports a ban on toxic pesticides in favor of organic practices. Our choices encourage the protection of the people who help put food on our table daily by purchasing organic products. For more information on how organic is the right choice for consumers and the farmworkers that grow our food, see the Beyond Pesticidesâ€™ webpage,Â Health Benefits of Organic Agriculture.Â
Lastly, suicide is the tenth leading cause of death among adults (3rd for adolescents) in the U.S., with more than 34,000 individuals succumbing to the disease annually. Suicidal thoughts and behaviors are dangerous and harmful and are therefore considered a psychiatric emergency. An individual experiencing these thoughts should seek immediate assistance from a health or mental health care provider. If you or someone you know is in an emergency, call theÂ National Suicide Prevention LifelineÂ at 1-800-273-TALK (8255) or 911 immediately.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.