User talk:Equercioli

To shed light on Petridou’s concern that a confounding variable may be raising suicide rates in the sunny summer months, Quercioli (2012) instead considered a new instrument for changing sunlight alone — leaving unaffected other seasonal factors associated to summer. She looked at the three north-south strips of neighboring counties, spanning the three time zone lines. Their only relevant difference is the sunlight around sunset or sunrise. Those living on the West side of a time zone line enjoy one less hour of light at night, compensated by an extra hour of light in the morning. But since most people rise after sunrise but sleep long after sunset, those on the West side enjoy an hour less sunlight daily. Consistent with the hypothesis that sunlight by itself reduces suicide rates, Quercioli (2012) finds that suicide rates in counties on the West side of each of the three time-zone lines in the USA had an 8% higher suicide rate in the years 1979 to 2007.