Abstract
OBJECTIVE
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.
METHOD
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.
RESULTS
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.
CONCLUSIONS
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.
TY - JOUR
T1 - Seasonal variation in the occurrence of homicide in Finland.
AU - Tiihonen,J,
AU - Räsänen,P,
AU - Hakko,H,
PY - 1997/12/16/pubmed
PY - 1997/12/16/medline
PY - 1997/12/16/entrez
SP - 1711
EP - 4
JF - The American journal of psychiatry
JO - Am J Psychiatry
VL - 154
IS - 12
N2 - OBJECTIVE: 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. METHOD: 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. RESULTS: 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. CONCLUSIONS: 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.
SN - 0002-953X
UR - https://www.unboundmedicine.com/medline/citation/9396950/Seasonal_variation_in_the_occurrence_of_homicide_in_Finland_
DB - PRIME
DP - Unbound Medicine
ER -
