Objective: To estimate the relationship between antiallergy drug prescription rates and suicide across the United States and over time. The relationship between allergy, allergens, and suicidal behavior and suggestions of a possible immune mediation led us to hypothesize that intranasal corticosteroids, known to reduce local airway production of T-helper cell type 2 cytokines, may be associated with reduced risk of suicide relative to antihistamines, which only secondarily affect cytokine production.
Method: The authors evaluated the relationship of suicide rates at the county level in the United States (N = 120,076 suicides) with prescriptions for intranasal corticosteroids and nonsedating antihistamines, in interaction with antidepressant prescriptions and other socioeconomic variables, for the period from 1999 to 2002. Suicide rate data were derived from state vital record systems based on local death certificate registries, and county-level allergy and antidepressant prescription data were obtained from IMS Health Incorporated (Plymouth Meeting, Pennsylvania).
Results: The prescription volume of intranasal corticosteroids was associated with a lower suicide risk (P = .0004), while that of antihistamines was associated with a modestly greater suicide risk (P = .0001). Adjustment for antidepressant prescriptions did not affect these relationships.
Conclusions: This is the first study, to our knowledge, to find a possible association between completed suicide and medications for allergic rhinitis and also the first report of an association of intranasal corticosteroid use with a lower suicide rate. This association should be considered preliminary and deserving of further investigation.
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