Everything in the world has every effect, though on different people, is one possible interpretation of the meaning of this study:
“Effect of climate and seasonality on depressed mood among twitter users,” Wei Yang, Lan Mu [pictured here], and Ye Shen, Applied Geography, Volume 63, September 2015, Pages 184–191. (Thanks to Tom Gill for bringing this to our attention.) The authors, at the University of Georgia, explain:
“we study the effect of climate and seasonality on the prevalence of depression in Twitter users in the U.S. Text mining and geospatial methods are used to detect tweets related to depression and their spatiotemporal patterns at the scale of Metropolitan Statistical Area. We find the relationship between depression rates, climate risk factors and seasonality are varied and geographically localized. The same climate measure may have opposite association with depression rates at different places.”
In this chart, the study’s authors try to make clear their reasoning:
