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Pesticides and depression: The great unknown

spraySeveral years ago I was a member of a team of journalists who wrote two award-winning series on migrant farm workers in Florida. I focused on working conditions, especially in the fields. I learned a lot about the pesticides, fungicides and herbicides sprayed on our food and the people who harvest that food.

I have not looked at a tomato, migrant farm worker or my yard the same way since. And now we have more reason for concern.

A study recently published in the American Journal of Epidemology suggests a link between pesticide exposure and depression. Researchers collected detailed pesticide use history from farmers recruited in 1998–2000 in France. Among 567 farmers aged 37–78 years, 83 (14.6%) self-reported treatment or hospitalization for depression.

Researchers then used models to estimate hazard ratios and confidence intervals for specific pesticides. The results were startling: Farm workers who used herbicides were more than twice as likely to have been treated for depression.

Why should you care about depression among farm workers in France? Because the strongest link was between workers exposed glyphosateto herbicides and the most popular herbicide in the United States is probably in your garage: Round-up.  The active ingredient in Round-up is glyphosate and a the EPA estimates about 100 million pounds are applied to U.S. farms and lawns every year.

I don’t know if the limits France puts on the use of herbicides containing glyphosate are more strict or lenient than those in the U.S. I do know this: Migrant farm workers – many undocumented – avoid hospitals and clinics. They cannot afford medical treatment and do not want to interact with anyone who might report them as illegal.

I also know that depression is not a widely recognized, accepted or treated illness in their homelands, rural areas of Mexico and Guatemala. So, you’re asking people to identify an illness they don’t even know exists.

In the research I did for our project, I also learned that the most common violations in the fields are improper mixing and application of pesticides in the fields. In Florida, training is required for pesticide applicators and there are prohibitions on spraying fields when workers are present or allowing them to return to fields too soon after pesticides have been applied.

Many farm workers will tell you that spray has drifted to the area of a field where they are working. You will hear stories of shortness of breath, skin rashes, weakness or vomiting when the smell of chemicals is strong. Many will also tell you they do not complain – for fear of losing their jobs or being deported.

We also need to understand that farmland sprayed with pesticides cover hundreds of square miles and as budgets have been cut, so have the number of inspectors who monitor pesticide use. Consider, too, that surprise inspections are rare. Most are scheduled in advance with plenty of time to clean up potential violations.

Then there is the issue of language. We found most inspectors in Florida did not speak Spanish, Creole or Canjobal  and that workers very often could not speak or read English.

What I’m trying to say is that although the study of French farm workers merely suggests a possible link between pesticides and depression, we need to take this news very seriously. We are constantly exposed pesticides – in our yards and at the grocery store.

While the EPA sets limits on the amount of a particular pesticide that can be used on specific crops, there is no testing of the synergistic effect of combining all those pesticides in one human being, meaning we don’t know how they will interact in our bodies.

If there is anything we have learned about depression it is that we still have much to learn about depression. The human brain remains a mystery. However, we do know that the brain is a part of the human body – a fact that policy makers, insurance companies and even physicians seem to overlook when dealing with mental illness.

What it comes down to – as it does with so many things pertaining to mental illness – is this: You, the patient or loved one, must conduct your own research, ask questions and make your own decisions. Decades of stigma, ignorance and a lack research has left us without the knowledge we have about so many other illnesses, such as cancer and diabetes.

So, how important is that weed sprouting through a crack in you patio?

Pesticide spraying in a field image available from Shutterstock.

Pesticides and depression: The great unknown

Christine Stapleton

Christine Stapleton has been a journalist for 35 years. She is now an investigative reporter for The Palm Beach Post. In 2006, began writing a blog for PsychCentral called Depression on My Mind. Her latest blog, Addiction Matters, draws on her 19 years of sobriety and her coverage of the drug treatment industry in South Florida.

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APA Reference
Stapleton, C. (2013). Pesticides and depression: The great unknown. Psych Central. Retrieved on February 18, 2020, from


Last updated: 6 Aug 2013
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