Increased suicides during new year, but not during Christmas in Sweden: analysis of cause of death data 2006-2015.

Background: Previous studies have investigated the impact of the Christmas and New Year holiday on suicide rates. However, no such data has yet been published on Swedish suicides.Aims: To examine the occurrence of suicides on these dates in Sweden between 2006 and 2015.Methods: The suicide count for each date between December 15th and January 15th was obtained from the Swedish cause of death registry. The observations were transformed to Z-scores to enable calculation of p-values.Results: A small but non-significant decrease in suicides was observed on Christmas and New Year's Eve. A significant spike was found on New Year's Day (NYD) (Z=3.40; p<.001), and these excess suicide occurred mainly among men aged 15-24 and 45-64. However, the number of suicides were somewhat lower than expected on the 31st of December (Z=-1.58; p=.115).Discussion: The noted increase in suicide on NYD is in line with previous research from other countries. However, the decrease in suicides on the day before NYD suggests a delay rather than a spontaneous increase of suicides. Possible mechanisms to explain this phenomenon are discussed, such as the broken promise effect, increased alcohol consumption, or lower help-seeking and accessibility to care.