Amber Todd and Jeanette Manger
The correlation between sunlight and mental health has been long studied and is even involved in the development of Seasonal Affective Disorder (SAD), with subsequent development of light therapy for affected individuals. This points towards the question of the effects of varying levels of daily sunlight in the United States on rates of suicide – a reflection of the extreme state of suboptimal mental health. I have ventured to study this question, using publicly available data on the daily sunlight levels in various states in the U.S. during each month of the year and the rates of suicide in those respective states and months. I analyzed and compared average daily sunlight for each month of the years 2001-2010 for each state to determine where each state and month was relative to the mean using descriptive statistics and Z-scores. Then, I analyzed the average suicide rates for those corresponding values to determine where each state and month was relative to the mean again using descriptive statistics and Z-scores. The sunlight and suicide rates data were then compared with each other using a stepwise linear regression to determine if there was a significant correlation. While there were no outlying sunlight levels or suicide rates for each state and month, it appeared that there were numerous states and months with sunlight levels and suicide rates in the same direction, rather than opposite, which contradicts the hypothesis. Upon linear regression analysis, it was found that there was no significant correlation between daily sunlight levels and suicide rates (P > 0.16). These findings suggest that the link between sunlight levels and suicide rates is likely multifactorial, and consideration of other contributing factors would be of benefit.
Amin, A. (2020). The Effects of Daily Sunlight Levels on Suicide Rates. Wright State University. Dayton, Ohio.