The epidemiology of homicide in Italy by season, day of the week and time of day

Circadian and seasonal rhythms have an impact on the risk of violent death in humans, with more evidence available in suicide than in homicide. This study set out to investigate the pattern of deaths by homicide in Italy, taking into account the month, the day of the week and the time of day when the homicidal incident happened. Data based on official statistics on deaths by homicide (n 1/4 3894) from 2003 to 2008 were analysed by spectral analysis and circular statistics techniques based on the Rayleigh test. Homicides showed seasonal distribution with a bimodal pattern, with summer (July and August) and winter (December and January) peaks over the other seasons. Homicides also peaked on Sundays and Mondays and were at their highest at night-time (00:00 to 5:59 hours). These rhythms in homicide victimization could be accounted for by social factors - within the framework of the routine activity theory - by psychological factors, including those leading to domestic violence, and by biological factors, including those impacting on impulse dyscontrol. The identification of risk or protective factors involved in the victim's surviving or succumbing to an assault might be important for the prevention of the worst outcome of injury at large, suicides and accidents included.