Can allergic exposure provoke psychological symptoms? A double-blind test.

Clinical ecologists report that exposure to allergens can induce cognitive and emotional symptoms as well as somatic symptoms in susceptible individuals, but controlled tests are meager. In a test of the hypothesis that sublingual exposure to allergens would produce cognitive-emotional symptoms in allergy patients, double-blind provocative testing was conducted at an allergy clinic; 30 allergy patients complaining of at least one psychological symptom were selected. Self-report, heart-rate, and several mood and psychological performance measures were obtained. MMPI scores indicated a pathological sample. Reported cognitive-emotional symptoms were greater for allergens than for placebos (p = 0.001), while placebo symptoms were equal to base rate. Greater variability of heart rate change was found for allergens than for placebos (p = 0.008). Severe reactions occurred more frequently to allergens (p = 0.008). Severe reactions occurred more frequently to allergens (p = 0.02). Other dependent measures were not affected by the allergens or the placebos. It is concluded that allergens may contribute to psychopathology in some individuals.