Findings from a statistical analysis in the American Journal of Preventive Medicine reveal the association of states' alcohol policy changes with population-level changes in homicide rates

Ann Arbor, June 24, 2024 – Alcohol consumption is involved in a large proportion of homicides and suicides each year in the United States, but there has been limited evidence on how policies targeting alcohol use influence violence. A statistical analysis in the American Journal of Preventive Medicine, published by Elsevier, indicates that more restrictive alcohol policy environments are associated with a reduction in specific states’ homicide rates.

Lead investigator James P. Murphy, PhD, RAND Corporation, Santa Monica, CA, says, "Previous studies have found a significant relationship between some state-level alcohol policies, such as the level of taxation and age-based restrictions, and crime rates, showing that more restrictive alcohol regulations are associated with a lower likelihood of alcohol involvement among homicide victims. However, the effects of alcohol policies on population-level homicide and suicide rates are not well-understood."

The researchers assessed the association of alcohol policy changes with population-level changes in homicide and suicide rates using the Alcohol Policy Scale (APS), an established and comprehensive alcohol policy index that measures state-year alcohol policy environments. Higher APS percentile scores are indicative of more restrictive alcohol policies. The study sample included all 50 US states. Vital deaths data were drawn from the National Vital Statistics System (NVSS).

To estimate the association between changes in a state’s APS score and changes in its homicide and suicide rates using data from 2002 to 2018, investigators applied a recently developed statistical model that, in similar policy settings, reduces bias in estimating the effects of policy changes on state-level rate outcomes compared to conventional approaches.

Dr. Murphy continues, “We found that adopting more restrictive alcohol policies was associated with a reduction in homicide rates, but not suicide rates. Based on our results, we would expect a nationwide increase in policy restrictions equivalent to a shift from the 25th to 75th percentile of the APS score would correspond with 1200 fewer homicides annually."

More than 74,000 individuals died of homicide or suicide in 2021 in the US. While many homicide and suicide decedents are not tested for blood alcohol content (BAC), among those tested, over 40% had a measurable BAC level. A recent meta-analysis estimated that the percentage of deaths attributable to alcohol among those with known BAC levels or intoxication status was 29% for all homicides (considering alcohol use only by the offender) and 21% for all suicides. These findings suggest that alcohol regulations may have an important role to play in addressing violence-related morbidity and mortality, including the growing number of firearm deaths.

Dr. Murphy concludes, "More restrictive alcohol policies may provide a promising approach to addressing the recent increases in homicides in the US. Further research is needed to identify the particular policies that are most effective, as well as to identify the particular mechanisms through which they affect homicide rates."