Examining the Link Between Depression and Seasonal Allergies

• Hamilton Rating Scale for Depression-Seasonal Affective Disorder Version (SIGH-SAD) [ Time Frame: Measured before and then during the peak fall or spring pollen period ] [ Designated as safety issue: Yes ]
  

• Hypomania Interview Guide (HIGH-SAD) [ Time Frame: Measured before and then during the peak fall or spring pollen period ] [ Designated as safety issue: Yes ]
  
• Burns Anxiety Inventory [ Time Frame: Measured before and then during the peak fall or spring pollen period ] [ Designated as safety issue: No ]
  
• Buss Aggression Questionnaire [ Time Frame: Measured before and then during the peak fall or spring pollen period ] [ Designated as safety issue: No ]
  
• Allergy Symptom Severity Assessment (ASSA) Questionnaire [ Time Frame: Measured before and then during the peak fall or spring pollen period ] [ Designated as safety issue: No ]
  
• Serum cytokine, tryptophan (TRP), and kynurenine (KYN) concentrations [ Time Frame: Measured before and then during the peak fall or spring pollen period ] [ Designated as safety issue: No ]
  
• Nasal secretion test [ Time Frame: Measured before and then during the peak fall or spring pollen period ] [ Designated as safety issue: No ]
  
• Sleep logs [ Time Frame: Measured over 1 week during pre- or post-pollen and peak pollen period ] [ Designated as safety issue: No ]
  
• Actiwatch [ Time Frame: Measured after the pre-pollen and peak pollen visits for 24 hours a day for 1 week ] [ Designated as safety issue: No ]
  
• Beck Depression Inventory II (BDI-II) [ Time Frame: Measured during the peak pollen period ] [ Designated as safety issue: Yes ]
  
• Pittsburgh Sleep Quality Index (PSQI) [ Time Frame: Measured during the peak pollen period ] [ Designated as safety issue: No ]
  

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.