Harvard Study Links Seasonal Peaks in Mass Shootings and Suicides to Summer Months
New research led by a Harvard Medical School clinical fellow at Brigham and Women’s Hospital indicates that annual peaks for both mass shootings and suicides in the U.S. occur within days of each other in late June and July. Conversely, the lowest points for both events are observed during the winter months, between December and February. The study, published in the Journal of Biological Rhythms, analyzed 3,305 mass shootings and 360,827 suicide deaths between January 2014 and October 2021, using publicly available data from sources like the Gun Violence Archive and the CDC. Mark Czeisler, the lead author, noted that while mass shootings are significantly rarer than suicides, they show a 613% difference between their summertime peak and winter valley, compared to a 12% rise for suicides. The study suggests that many mass shootings are fundamentally suicidal acts, a theory supported by previous research indicating that a growing percentage of shooters die during these events. 
