Research News: Allergy and Depression

By Teodor T. Postolache, MD and Darryl Robert, MS, RN

[Winter 2007; Vol. 33, No. 2; Pg. 10]

Seasonal allergy affects 10%-30% of adults and up to 40% of children. Persons with a personal or family history of major depression have an even higher prevalence. Further, clinical depression negatively influences immune response and increases the likelihood of seasonal allergies and other immune-related illnesses. Allergies result in increased cytokine release which could trigger or worsen depression, anxiety or cognitive symptoms.

In addition, we recently reported results of ongoing behavioral studies of brown Norway rats sensitized with tree pollen vs. saline-treated controls, finding significantly increased anxiety (e.g., reduced time in open field maze arms) and depressive-like symptoms (e.g., longer immobility and decreased swimming time in forced-swim test). In human brains, we found significant gender and suicide interactions of interleukin (IL)-1β/IL-4 gene expression and increased levels of IL-5 gene expression in the orbital-frontal cortexes of female suicide victims suggestive of seasonal inflammatory responses affecting brain structures. In another freshly completed study from our group, college students with self reported sensitivity to tree pollen also reported a greater seasonality of mood and a greater proportion of seasonal affective disorder of non-winter type. Finally, in a large epidemiological suicide study, we found a significant relationship between tree pollen peaks and nonviolent suicides in younger women.

To further support the hypothesized relationship between peaks in environmental aeroallergens and mood decompensation, particularly in persons with mood disorders, the University of Maryland Psychiatry Department’s Mood and Anxiety Program (MAP) is currently conducting an NIMH-funded, IRB approved,  case-control study following 100 stable patients with mood disorders through their specific pre- and peak-pollen periods. In this study, the MAP will identify allergy atopy using allergen-specific IgE. We hypothesize that compared to their baseline, individuals with seasonal allergies will have a more pronounced worsening in their depression scores during their specific allergy seasons than matched controls without seasonal allergy.

To complete this study, the MAP is seeking stable patients with Major Depressive Disorder or Bipolar Disorder independent of any history of allergy. Patients will be compensated for the time involved in the study participation. To facilitate completion of this study, we request referrals from and collaboration with clinical mental health providers throughout Maryland and DC. Those collaborators who make significant contributions to the study could share in research report authorship and be invited to collaborate on future projects. Also, the knowledge about their patient’s allergy status (at the end of the study) may improve overall quality of care. This study will be instrumental in improving our understanding the aeroallergen-depression link and lend evidence for subsequent interventions that might weaken the link, lessen the seasonal worsening in mood disorders and flatten the peak of suicide in spring.  If you have patients who might be interested in the study, contact, or let them contact Darryl Roberts at 410-706-2003. If you are interested in collaborating on the study, contact the PI, Dr. Teodor Postolache at 410-706-2323.