Major Finding: IgE levels predicted worsening of depressive symptoms during high pollen season in patients with recurrent mood disorders.
Data Source: A blinded study of 100 patients.
Disclosures: The National Institute of Mental Health funded the study. The researchers had no relevant financial disclosures to make.
Allergen-specific immunoglobulin E and allergy symptoms are associated with worsening of depression scores in patients with mood disorders who are exposed to seasonal pollen peaks, preliminary results from a novel study suggest.
“We already know that depression is a very common disorder, but allergy is even more common,” Dr. Partam Manalai of the mood and anxiety program in the department of psychiatry at the University of Maryland School of Medicine, Baltimore, said at a press briefing.
“One in every two people might have some kind of sensitivity to some allergen, and one in five people may have allergic rhinitis. During exacerbations of allergic rhinitis, people experience worsening of mood, cognition, and overall well-being.”
Dr. Manalai went on to note that there is a spring peak in pollen count that corresponds with tree pollen, while there is a somewhat smaller fall peak in pollen count, which corresponds with ragweed and grass pollen. At the same time, he said, several previously published studies have found a peak in the rate of completed suicides in the spring, and a somewhat smaller peak in the fall.
“To our knowledge, this is the first report of a biological marker of allergic sensitization (allergen-specific IgE) predicting worsening in depressive symptoms during the high pollen season,” Dr. Manalai said.
“In a group of patients with allergy and depression, prophylactic treatment of these conditions may prevent worsening of mood during peak allergen season. Our findings may be conducive to research on new preventative and therapeutic targets in the management of mood disorders.”
In the study, researchers blinded to the patients' IgE status evaluated 100 patients from Baltimore and Washington, with diagnoses of recurrent mood disorder– once during a low pollen period and once during the preceding or subsequent peak high pollen period.
Patients taking antihistamines and decongestants were included in the analysis, but those with active substance-related or psychotic disorders were excluded, as were those taking montelukast or intranasal corticosteroids.
The researchers administered the Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorder Version and the Allergy Symptom Severity Assessment and compared the scores during the low and high pollen periods.
As recommended by the National Allergy Bureau, they conducted volumetric sampling for pollen in grains/m
The mean age of patients was 44 years, and 60 were men. Nearly half (47) were IgE positive for tree and/or ragweed pollen, while the rest (53) were IgE negative.
Dr. Manalai reported that changes in typical depression scores were significantly related to worsening of allergy symptoms (P = .008) while changes in atypical depression scores were significantly related to allergy-specific IgE positivity (P = .033), but not to worsening of allergy symptoms.
“The worse the allergy symptoms, the worse the depression scores,” Dr. Manalai said.
Specifically, during low pollen season, the mean SIGH-SAD score for those in the allergen-specific IgE-positive group who had typical depression was 11.77, compared with a mean score of 9.8 for their counterparts in the allergen-specific IgE negative group. The SIGH-SAD score was also higher for those in the allergen-specific IgE-positive group who had atypical depression (a mean of 5.27, compared with a mean of 4.37 for their counterparts in the allergen-specific IgE negative group).
During high pollen season, the mean SIGH-SAD score for those in the allergen-specific IgE-positive group who had typical depression was 11.54, compared with a mean score of 9.76 for their counterparts in the allergen-specific IgE negative group.
The SIGH-SAD score was also higher for those in the allergen-specific IgE-positive group who had atypical depression (a mean of 6.9, compared with 5.13 for their counterparts in the allergen-specific IgE negative group).
In a later interview, lead author Dr. Teodor T. Postolache, who directs the University of Maryland psychiatry department's mood and anxiety program, pointed out that these mean scores “need to be adjusted for C-reactive protein. C-reactive protein changes were used in the models to adjust for and minimize the masking effects of nonallergic inflammation during the duration of the study (such as virus infections, sinus infections, to name a few).”