Tiihonen J, Räsänen P, Hakko H
Department of Forensic Psychiatry, University of Kuopio, Finland.
Am J Psychiatry. 1997 Dec;154(12):1711-4. doi: 10.1176/ajp.154.12.1711.
Although seasonal variation in impulsive aggression related to circannual rhythms of central serotonin neurotransmission is a topic of current interest, there is little firm knowledge on seasonality in the occurrence of homicide. Longitudinal studies on the seasonal rhythms of platelet imipramine binding and L-tryptophan levels have placed the circannual peaks around January and February and the nadirs around May and August. The aim of this study was to test the hypothesis that the number of homicides is the lowest during winter and the highest during spring and summer. A secondary hypothesis was that the seasonal variations in homicides and violent suicides are correlated.
The largest database on the monthly occurrence of homicide thus far (N = 4,553) was used in this study, in which the monthly occurrence of all murders and manslaughters in Finland during the years 1957-1995 was analyzed.
During winter the homicide rate was 6% below the expected rate. Correspondingly, during summer there was a 6% elevation above the expected homicide rate, but no significant peak was observed in spring. There was a significant association between the monthly occurrence of homicides and violent suicides but not between homicides and nonviolent suicides.
The results suggest that a seasonal variation in the occurrence of homicide exists. On the basis of current literature, it could be hypothesized that this seasonal variation and the correlation between the monthly occurrence of homicides and violent suicides are associated with the observed circannual rhythms of serotonin transmission.
尽管与中枢5-羟色胺神经传递的年节律相关的冲动攻击性的季节性变化是当前人们感兴趣的话题，但关于杀人案发生的季节性却知之甚少。对血小板丙咪嗪结合和L-色氨酸水平季节性节律的纵向研究表明，年节律高峰出现在1月和2月左右，低谷出现在5月和8月左右。本研究的目的是检验杀人案数量在冬季最低而在春季和夏季最高这一假设。第二个假设是杀人案和暴力自杀案的季节性变化相关。
本研究使用了迄今为止关于杀人案月度发生情况的最大数据库（N = 4553），其中分析了1957年至1995年芬兰所有谋杀和 manslaughter（此处原文可能有误，推测为“manslaughter”，意为过失杀人）案件的月度发生情况。
冬季杀人案发生率比预期发生率低6%。相应地，夏季杀人案发生率比预期发生率高6%，但春季未观察到明显高峰。杀人案的月度发生情况与暴力自杀案之间存在显著关联，但与非暴力自杀案之间不存在显著关联。
结果表明杀人案的发生存在季节性变化。根据当前文献，可以推测这种季节性变化以及杀人案和暴力自杀案的月度发生情况之间的相关性与所观察到的5-羟色胺传递的年节律有关。
