Incidence and risk factors of homicide-suicide in Swiss households: National Cohort study

PLoS One. 2013;8(1):e53714. doi: 10.1371/journal.pone.0053714. Epub 2013 Jan 9.

Abstract

Background: Homicide-suicides are rare but catastrophic events. This study examined the epidemiology of homicide-suicide in Switzerland.

Methods: The study identified homicide-suicide events 1991-2008 in persons from the same household in the Swiss National Cohort, which links census and mortality records. The analysis examined the association of the risk of dying in a homicide-suicide event with socio-demographic variables, measured at the individual-level, household composition variables and area-level variables. Proportional hazards regression models were calculated for male perpetrators and female victims. Results are presented as age-adjusted hazard ratios (HR) with 95% confidence intervals (95%CI).

Results: The study identified 158 deaths from homicide-suicide events, including 85 murder victims (62 women, 4 men, 19 children and adolescents) and 68 male and 5 female perpetrators. The incidence was 3 events per million households and year. Firearms were the most prominent method for both homicides and suicides. The risk of perpetrating homicide-suicide was higher in divorced than in married men (HR 3.64; 95%CI 1.56-8.49), in foreigners without permanent residency compared to Swiss citizens (HR 3.95; 1.52-10.2), higher in men without religious affiliations than in Catholics (HR 2.23; 1.14-4.36) and higher in crowded households (HR 4.85; 1.72-13.6 comparing ≥2 with <1 persons/room). There was no association with education, occupation or nationality, the number of children, the language region or degree of urbanicity. Associations were similar for female victims.

Conclusions: This national longitudinal study shows that living conditions associated with psychological stress and lower levels of social support are associated with homicide-suicide events in Switzerland.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Age Distribution
  • Aged
  • Aged, 80 and over
  • Child
  • Cohort Studies
  • Death
  • Family Characteristics*
  • Female
  • Homicide / statistics & numerical data*
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Risk Factors
  • Suicide / statistics & numerical data*
  • Switzerland / epidemiology
  • Young Adult

Grant support

The Swiss National Cohort is funded by the Swiss National Science Foundation (grant No. 3347C0-108806, see www.snf.ch)The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.