Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Scientific Correspondence
  • Published:

Tree pollen peaks are associated with increased nonviolent suicide in women

Molecular Psychiatry volume 10, pages 232–235 (2005)Cite this article

SIR—Research on seasonality of suicide has identified a highly replicated and robust peak in late spring and a somewhat less consistent peak in late summer and early fall.1 While a number of psychosocial and environmental factors, such as increased exposure to light in the spring, have been suggested to be associated with the spring peak, none satisfactorily explains the temporal association of the peak in suicide with the proposed environmental trigger. Based on the influence of cytokines on mood, cognition, and behavior in healthy individuals2 and patients with medical and psychiatric conditions,3,4,5 the reciprocal immune–brain interactions,6 and the cytokine expression during allergic reactions, we hypothesized that tree pollen (which peaks in spring) and ragweed pollen (which peaks in late summer/early fall) may act as environmental triggers for suicide in vulnerable individuals. We explored this hypothesis by comparing the suicide rates before, during and after periods of peak atmospheric pollen.

Tree and ragweed pollen data were obtained from the American Academy of Allergy, Asthma, & Immunology for the years 1995–1998 for the continental US and Canada. Periods of allergen exposure were derived from histograms expressing pollen counts as particles per cubic meter (p/m3) on a log scale from 0 to 1000 (y-axis) by months (x-axis) within each year. Raters identified three periods for each allergen in time units of quarter-months at each location for up to 4 years divided as follows: a prepollen period (pollen counts <10 p/m3 for trees and <mid-way on the log scale between 1 and 10 p/m3 for ragweed), a peak-pollen period (>100 p/m3 for trees and >mid-way on the log scale between 10 and 100 p/m3 for ragweed), and a postpollen period when concentrations returned to the prepollen levels. Intervals with intermediate pollen counts were discarded.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to the full article PDF.

USD 39.95

Prices may be subject to local taxes which are calculated during checkout

References

  1. Hakko H et al. Acta Psychiatr Scand 1998; 98: 92–97.

  2. Reichenberg A et al. Arch Gen Psychiatry 2001; 58: 445–452.

  3. Capuron L, Dantzer R . Brain Behav Immun 2003; 17(Suppl 1): S119–S124.

  4. Licinio J, Wong ML . Mol Psychiatry 1999; 4: 317–327.

  5. Wichers M, Maes M . Int J Neuropsychopharmacol 2002; 5: 375–388.

  6. Maier SF . Brain Behav Immun 2003; 17: 69–85.

  7. Timonen M et al. Mol Psychiatry 2003; 8: 738–744.

  8. Nelson RJ et al. Seasonal Patterns of Stress, Immune Function, and Disease, 1st edn. Press Syndicate of the University of Cambridge, Cambridge University Press: Cambridge, UK, 2002.

    Book  Google Scholar 

  9. Bode L, Ludwig H . Clin Microbiol Rev 2003; 16: 534–545.

  10. Mann JJ . Nat Rev Neurosci 2003; 4: 819–828.

Download references

Acknowledgements

We would like to thank Dr Esther Sternberg for essential theoretical as well logistical help at the initiation of this study and comments on an earlier draft of the manuscript, Dr Dean Metcalfe for important early insights in seasonal allergy, which helped with the conceptual framework of the study design, Dr John Bartko for initial statistical advice, and to Dr Faheem Syed for help with pollen data management. We are also grateful to R Mittendorf and Drs Katayoun Khosravani and Darshita Shah for their help with sunlight data management. Finally, we would like thank those members of American Academy of Allergy, Asthma, & Immunology who generously donate their time and expertise in participating in the Aeroallergen Network. The study was supported by DC-Department of Mental Health, Washington, DC (Dr Postolache, Principal Investigator).

Author information

Authors and Affiliations

  1. Mood and Anxiety Disorder Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA

    T T Postolache, J W Stiller & H D Komarow

  2. DC DMH, St Elizabeth's Hospital Psychiatry Residency Training Program, Washington, DC, USA

    T T Postolache, J W Stiller, M A Goldstein, S S Shreeram, R Zebrak, C M Thrower, J Volkov, M J No, I Volkov, J Redditt, M Parmar, F Mohyuddin & M Moca

  3. Section on Developmental Genetic Epidemiology, the National Institute of Mental Health, the National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA

    R Herrell & K Merikangas

  4. Department of Medical Psychology, Uniform Services University, Bethesda, MD, USA

    K J Rohan

  5. Department of Preventive Medicine and Biometrics, Uniform Services University of the Health Services, Bethesda, MD, USA

    C Olsen

  6. Section on Neuroendocrine Immunology and Behavior, the National Institute of Mental Health, the National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA

    L H Tonelli

  7. Genetics and Genomics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, the National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA

    H D Komarow

Authors
  1. T T Postolache
    View author publications

    Search author on:PubMed Google Scholar

  2. J W Stiller
    View author publications

    Search author on:PubMed Google Scholar

  3. R Herrell
    View author publications

    Search author on:PubMed Google Scholar

  4. M A Goldstein
    View author publications

    Search author on:PubMed Google Scholar

  5. S S Shreeram
    View author publications

    Search author on:PubMed Google Scholar

  6. R Zebrak
    View author publications

    Search author on:PubMed Google Scholar

  7. C M Thrower
    View author publications

    Search author on:PubMed Google Scholar

  8. J Volkov
    View author publications

    Search author on:PubMed Google Scholar

  9. M J No
    View author publications

    Search author on:PubMed Google Scholar

  10. I Volkov
    View author publications

    Search author on:PubMed Google Scholar

  11. K J Rohan
    View author publications

    Search author on:PubMed Google Scholar

  12. J Redditt
    View author publications

    Search author on:PubMed Google Scholar

  13. M Parmar
    View author publications

    Search author on:PubMed Google Scholar

  14. F Mohyuddin
    View author publications

    Search author on:PubMed Google Scholar

  15. C Olsen
    View author publications

    Search author on:PubMed Google Scholar

  16. M Moca
    View author publications

    Search author on:PubMed Google Scholar

  17. L H Tonelli
    View author publications

    Search author on:PubMed Google Scholar

  18. K Merikangas
    View author publications

    Search author on:PubMed Google Scholar

  19. H D Komarow
    View author publications

    Search author on:PubMed Google Scholar

Corresponding author

Correspondence to T T Postolache.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Postolache, T., Stiller, J., Herrell, R. et al. Tree pollen peaks are associated with increased nonviolent suicide in women. Mol Psychiatry 10, 232–235 (2005). https://doi.org/10.1038/sj.mp.4001620

Download citation

  • Published:

  • Issue date:

  • DOI: https://doi.org/10.1038/sj.mp.4001620

This article is cited by

Search

Advanced search

Quick links