Examining the Link Between Depression and Seasonal Allergies

Study Overview
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Brief Summary
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This study will examine whether spring and fall seasonal depression in individuals with high sensitivity to pollen is linked to seasonal increases in tree and ragweed pollen.

Detailed Description
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Those who suffer from depression have their normal lives interrupted by symptoms such as persistent sad thoughts, inability to feel pleasure, and potential suicide. Suicide and depression peak in the spring and fall. Worsening of depression, admission to a hospital for depression and bipolar depression, and use of electroconvulsive therapy for treatment of depression all peak in the spring. Although seasonal affective disorder (SAD), in which depression corresponds with seasonal changes, is commonly associated with the winter subtype, SAD is actually more prevalent as the spring subtype. Allergies, which also peak in the spring and fall, have been linked to depression. Allergic reactions release cytokines, which are proteins that mediate the immune system response when a foreign substance enters the body. Previous studies have found both that an increase in cytokines in otherwise healthy individuals causes depressive symptoms and that cytokines cause the chemical tryptophan (TRP) to switch from producing serotonin, a neurotransmitter associated with feelings of well-being, to producing kynurenine (KYN), a potentially toxic chemical. To determine whether and to what extent allergies are linked to depression, this study will compare depression levels of participants with and without allergies before and during peak times for seasonal allergies. Results from this study may be used in further research to examine the effects of allergy prevention on depression. Participants in this study will meet with researchers three times. At the first visit, they will be screened for allergies and give their demographic information. The timing of the second and third visits will depend on each participant's allergies. Those with spring allergies will be tested before and then during the spring allergy season. Those with fall allergies or with no allergies will be tested before and then during the fall allergy season. On the second and third visits questionnaires and clinical interviews will assess depression symptoms, and blood tests will be performed to measure chemical levels of cytokines, TRP, and KYN. During these visits participants will also be asked to complete a sleep log for 1 week. This will entail describing their sleep, activity, caffeine consumption, alcohol consumption, and use of sleep medications. A subgroup will wear an Actiwatch device, which electronically monitors sleep and wakefulness cycles, for 1 week, 24 hours a day.

Official Title
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Seasonality of Depression and Airborne Allergens

Conditions
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Depression

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of major depressive disorder or bipolar disorder Exclusion Criteria: Pregnancy or intention to become pregnant within the duration of the study Dependence on alcohol, cocaine, stimulants, benzodiazepines, marijuana, or opiates Major medical illness, including cancer, hepatitis, and autoimmune disease A winter subtype of seasonal affective disorder Diagnosis of psychotic disorder Positive result in Phadiatop allergy test, but negative result in tree or ragweed pollen IgE test

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 64 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental group<br>All participants testing positive for tree and ragweed pollen allergies, as determined by levels of immunoglobulin E (IgE) antibodies | |
| Control group<br>All participants testing negative for tree and ragweed pollen allergies, as determined by levels of IgE antibodies | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hamilton Rating Scale for Depression-Seasonal Affective Disorder Version (SIGH-SAD) |  | Measured before and then during the peak fall or spring pollen period | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hypomania Interview Guide (HIGH-SAD) |  | Measured before and then during the peak fall or spring pollen period | 
| Burns Anxiety Inventory |  | Measured before and then during the peak fall or spring pollen period | 
| Buss Aggression Questionnaire |  | Measured before and then during the peak fall or spring pollen period | 
| Allergy Symptom Severity Assessment (ASSA) Questionnaire |  | Measured before and then during the peak fall or spring pollen period | 
| Serum cytokine, tryptophan (TRP), and kynurenine (KYN) concentrations |  | Measured before and then during the peak fall or spring pollen period | 
| Nasal secretion test |  | Measured before and then during the peak fall or spring pollen period | 
| Sleep logs |  | Measured over 1 week during pre- or post-pollen and peak pollen period | 
| Actiwatch |  | Measured after the pre-pollen and peak pollen visits for 24 hours a day for 1 week | 
| Beck Depression Inventory II (BDI-II) |  | Measured during the peak pollen period | 
| Pittsburgh Sleep Quality Index (PSQI) |  | Measured during the peak pollen period | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Mood Disorders, Major Depressive Disorder, Bipolar Disorder, Tree Pollen, Ragweed Pollen, Rhinitis, Allergic, Seasonal, Allergens