Considering clinical and animal evidence suggesting a relationship between allergy and anxiety, we hypothesized that, from low to high aeroallergen exposure, changes in anxiety symptom scores in patients with primary mood disorders will correlate with changes in allergy symptom scores. We also anticipated that sensitization to tree pollen, as determined by allergen specific IgE antibodies, will predict a greater worsening of anxiety during exposure to tree pollen. 51 patients with unipolar or bipolar disorder (age: 19-63 years, 65% female) were recruited. Tree- pollen IgE positive subjects (12) were included as the experimental group and patients negative to a multi-allergen serological test (39) were included in the control group. Self reports of anxiety and allergy symptoms were obtained once during the peak airborne pollen counts and once during the period of low airborne pollen counts, as reported by two local pollen counting stations. Using linear regression models, we confirmed a significant positive association between allergy scores and anxiety scores (p<0.04); however, the IgE specific tree pollen positivity was not significantly associated with changes in anxiety scores. Because changes in anxiety scores relate to changes in depression scores, the relationship between allergy and anxiety involves states rather than only traits, and as such, our results lead to future efforts to uncover potential anxiety triggering, exacerbating or perpetuating role of allergens in vulnerable individuals.