Seasonal Affective Disorder: Illuminating the Latitude Hypothesis
Graceffo, James Michael
Doctor of Philosophy
Date of Defense:
August 21, 2015
Jeffrey Hayes, Dissertation Advisor/Co-Advisor Kathleen Bieschke, Committee Member Louis Georges Castonguay, Committee Member Eugene Edmund Clothiaux, Committee Member
Seasonal Affective Disorder College Students Depression
The present study investigated the relationship between meteorological variables and depressive symptoms. More specifically, we explored the effects of time of year (hours of daylight, or photoperiod, will serve as a proxy measure for time of year) and cloud cover (irradiance measures from surface radiation budget sites across the United States) on depression scores in both treatment and non-treatment seeking samples of college students. Previous research into the latitude gradient has neglected important environmental factors that can influence the level of light a person experiences day-to-day. We hypothesized that time of year and cloud cover would be inversely related to depression scores. The results failed to support the hypotheses, which is later discussed in greater detail.