Pesticides and Depression
By Michael R. Rosmann, Ph.D. and Lorann Stallones, M.P.H., Ph.D., Colorado State University
Many health care practitioners, even those in agricultural areas, are not aware that organophosphate and carbamate insecticide poisoning can lead to depression. There are established links between acute poisoning from organophosphate compounds and increased risk of suicide. Most of our common agricultural insecticides (e.g., Dursban, Lorsban, Aztec, Dyfonate, Thimet, Amaze, Furadan, Broot, to name but a few) contain one of these substances.
Acute exposures to organophosphates and carbamates produce headache, nausea, muscle twitching, diarrhea, excessive salivation and sweating, difficulty breathing and severe exposures can lead to pulmonary edema, seizures and death. Some researchers have suggested when the depression that results from acute poisoning is treated with selective serotonin reuptake inhibitors (e.g., Prozac, Zoloft, Paxil, Celexa and Luvox) there may be an increased risk of suicide.
Suicide is a serious issue in the agricultural population. In some areas farmers have been reported to be at higher risk of suicide than other working populations and than the general public. Exposures to organophosphate and carbamate insecticides, depression and suicide are aptly documented in a video entitled “Green Blood Red Tears,” available from Ag-Culture Media Project, 11503 Main Street, Middletown, KY 40243. These matters are getting attention in the scientific literature as well. Recent studies have suggested that the depression associated with an acute pesticide poisoning persists long after the initial episode. An excellent resource to address acute poisonings is "Recognition and Management of Pesticide Poisons" by J. Routt Reigart, M.D., and James R. Roberts, M.D., M.P.H. The book is available from the United States Environmental Protection Agency, 401 M Street Southwest (7506C), Washington, DC 20460. It can be ordered by calling (703) 305-7666. The manual is available in electronic format on the Internet at www.epa.gov/oppfead1/safety/healthcare/handbook/handbook.htm.
A number of laboratories offer tests for red blood cell acetylcholinesterase enzyme and plasma pseudocholinesterase levels. Depressions in plasma pseudocholinesterase and/or red blood cell acetylcholinesterase enzyme activities can be biochemical indicators of excessive organophosphate or carbamate absorption. The test is not widely available in all hospital and clinic laboratories. Many small hospitals and physician clinics may need to send out blood samples for analysis because they do not have the equipment to conduct the test locally. An important consideration that is often overlooked and hard to accomplish is the establishment a baseline cholinesterase level. The reference range is wide and many persons may experience a drop from baseline and still be within the normal range, so additional testing is required to determine if the cholinesterase level is continuing to drop, stabilizing, or rising.
It is important that health care providers have adequate information to provide education regarding the signs and symptoms related to working with these cholinesterase inhibiting chemicals. Many times farmers are not aware of the problems associated with exposures to these chemicals. Exposures can be through ingestion, inhalation and skin contact. Health care providers should be able to recommend personal protective equipment and steps that users of the chemicals can take to minimize exposures. Health care professionals need to ask questions about what types of chemicals have been used, and what types of personal protective equipment are being used. When prescribing medication for depression, clinicians should assess whether there has been an acute pesticide poisoning in the past which may have lead to the depression and should monitor these individuals closely for suicidal ideation. These are important considerations in the treatment of depression in individuals who have experienced an acute pesticide poisoning. Personal protective equipment is available from several suppliers, such as Gempler’s, Inc., P.O. Box 270, 100 Countryside Drive, Belleville, WI 53508, telephone: (800) 382-8473.
Green Blood, Red Tears (Movie)
In 1995, 43-year-old Kentucky tobacco farmer James Gray Goodman shot and killed himself in a cow pasture. This film examines why this tragedy occurred and why so many other farmers die by suicide each year. Viewers will learn how hard it is for those running small farms to effectively compete against large farms run by big business and how new technologies often make it harder for small farms to remain competitive. Questions are raised about whether Goodman's central nervous system was damaged by the chemicals contained in farming insecticides that can cause mood swings and serious depression.