Changes over time in homicides by women: a register-based study comparing female offenders from 1982 to 1992 and 1993 to 2005.

Background: The contribution of women to violent offending, including homicide, may be increasing as society changes.

Aims: The aim of this paper was to test for trends in homicide by women in Finland.

Methods: A retrospective register-based study was conducted by comparing two national cohorts: one from 1982 to 1992 and the other from 1993 to 2005.

Results: There was a small increase in the proportion of homicides committed by women over time, but the most striking difference between the cohorts was in the significantly higher frequency of alcohol abuse/dependence in the later cohort and of being under the influence of alcohol during the crime. Fewer perpetrators were regarded as lacking or being of diminished responsibility in the later cohort. The victims of the earlier cohort were emotionally closer to the offender than those of the later one.

Conclusions: In Finland, there have been changes in characteristics of women who commit homicide and their crimes over time, with the apparent development of a subgroup of women who kill who are much more like men who kill than women in the 1980s and early 1990s. Preventing substance abuse and marginalization are likely to be important ways of preventing homicide by both female and male perpetrators.