Summary: A U.S. study combining pollen and suicide data from over a decade shows that high pollen days are linked to a measurable rise in suicide risk. The risk increased incrementally with pollen levels, peaking at a 7.4% rise on the highest days.
Vulnerable groups—including those with mental health histories, white men, and Black individuals—were most affected. Researchers warn that as climate change extends pollen seasons, these risks may intensify, highlighting the need for improved forecasting, mental health awareness, and tailored care.
Key Facts
- Risk Increase: Up to 7.4% higher suicide rates on high-pollen days.
- Vulnerable Groups: Strongest effects in white men, but also notable in Black individuals and those with mental health histories.
- Future Threat: Climate change may double the impact by century’s end.
Source: University of Michigan
Beyond the sneezing and itchy eyes, high pollen seasons are now linked to a significant increase in suicide risk.
A new University of Michigan study found a 7.4% jump in deaths, suggesting the physical discomfort of allergies may trigger a deeper, more dangerous despair, an overlooked factor in suicide prevention.
The study indicates that allergies’ physiological effects, such as poor sleep and mental distress, may contribute to this increased risk.
“A small shock could have a big effect if you’re already in a vulnerable state,” said Joelle Abramowitz, associate research scientist at U-M’s Institute for Social Research. “We looked specifically at pollen from all different kinds of plants, including trees, weeds and grasses.”
The effect is incremental. Researchers divided pollen levels into four tiers and found the suicide risk rose with each group: it increased by 4.5% in the second level, 5.5% in the third and peaked at 7.4% in the fourth and highest category.
The study, funded by the American Foundation for Suicide Prevention and U-M ISR, combines daily pollen data from 186 counties of 34 metropolitan areas across the United States, with suicide data from the National Violent Death Reporting System between 2006 and 2018.
Abramowitz and co-authors Shooshan Danagoulian and Owen Fleming of Wayne State University said that while structural factors for suicide are well-researched, short-term triggers are less understood.
Pollen allergies are an ideal subject for this research, considering they are an exogenous shock—meaning they are external and not caused by an individual’s mental health status.
“During our study period, there were nearly 500,000 suicides in the U.S.,” Abramowitz said. “Based on our incremental data, we estimate that pollen may have been a contributing factor in up to 12,000 of those deaths over the period, or roughly 900 to 1,200 deaths per year.”
Vulnerable populations
Published in the Journal of Health Economics, the study also found that individuals with a known mental health condition or who had received prior mental health treatment had an 8.6% higher incidence of suicide on days with the highest pollen levels.
White men strongly drive the effect, but the study also found an unexpectedly high vulnerability among Black individuals.
“While our study’s data comes from the U.S., our findings likely apply globally,” Abramowitz said.
“This is supported by earlier research that found similar relationships in locations like Tokyo and Denmark. Our results, therefore, provide crucial new evidence that this phenomenon is a consistent, worldwide trend.”
Public health and awareness
The focus should be on public health and education, as reducing the number of pollen-producing plants isn’t a viable option, the researchers suggest. This includes more accurate pollen forecasting and better public communication.
Providing people with clear, timely information about high-pollen days allows them to take proactive steps. Additional recommendations are limiting outdoor activities, wearing a mask or having antihistamines on hand.
There is also a need for a broader approach to mental health awareness, the authors said. Health care providers, particularly those in primary care, can benefit from understanding the connection between environmental factors, such as pollen, and patient well-being.
This knowledge could help them tailor care more effectively, especially for vulnerable patients, and serve as a prompt to discuss mental health and stress management during high-pollen seasons or other periods of environmental stress.
“We should be more conscious of our responsiveness to small environmental changes, such as pollen, and our mental health in general,” Abramowitz said.
“Given our findings, I believe medical providers should be aware of a patient’s allergy history, as other research has also established a connection between allergies and a higher risk for suicide. I hope this research can lead to more tailored care and, ultimately, save lives.”
Key Questions:
A: Suicide deaths rose by up to 7.4% during days with the highest pollen levels.
A: The effect was strongest in white men, but also unexpectedly high among Black individuals and those with prior mental health conditions.
A: Allergies disrupt sleep and increase mental distress, which may worsen vulnerability to suicidal thoughts.
About this mental health and suicide research news
Author: Fernanda Pires
Source: University of Michigan
Contact: Fernanda Pires – University of Michigan
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Seasonal allergies and mental health: Do small health shocks affect suicidality?” by Joelle Abramowitz et al. Journal of Health Economics
Abstract
Seasonal allergies and mental health: Do small health shocks affect suicidality?
Suicide rates increased 37% in the US from 2000 to 2018; while structural factors are extensively studied, short-term triggers remain less understood. We examine the impact of small exogenous shocks – allergies triggered by seasonal pollen – on suicides.
Pollen allergies diminish cognitive function and disrupt sleep—predictors of suicidality. Combining disparate datasets across 34 localities in the United States from 2006 to 2018, we use a specification with granular fixed effects to identify the effect of pollen on suicides from daily variation in each.
We find that as pollen levels rise, the count of suicides in a county increases – up to 7.4% more suicides when pollen levels at their highest levels. We find that individuals with a known mental health condition or treatment have 8.6% higher incidence of suicides on days with highest pollen.
We also show that this effect is not spurious – Google searches for allergy and depression symptoms increase substantively as pollen levels rise.
These estimates are robust to multiple specifications. As climate change extends and intensifies the pollen season, we expect its impact to more than double the number of suicides by the end of the century.
These results point toward the importance of relatively small exogenous shocks on suicidality and the potential for relatively inexpensive and routine health care measures such as allergy testing and treatment to improve mental health.
