Substance use patterns and homicide in Finland, 2002–2022: Comparison of young and adult offenders

Due to the increase in the use of illicit drugs in western Europe, key policy stakeholders and researchers have increasingly focused on the drugs-violence nexus. However, previous research on changing substance use patterns among homicide offenders, particularly studies that consider alcohol and drugs simultaneously, remains limited. Comparative analyses of youth- versus adult-perpetrated homicides from a substance use perspective are particularly scarce. The current study addressed the research gaps using a unique Finnish dataset of homicides committed between 2002 and 2022 and comparing substance use among young (15-29-year-olds; n = 589) and adult (30+-year-olds; n = 1249) offenders. The findings point to significant changes in substance use patterns in homicides during the study period, especially with respect to youth homicides. Driven largely by a considerable drop in alcohol-related homicides among both youth and adults, the findings are consistent with previous literature suggesting that illicit drugs may be becoming proportionally more central than older patterns of substance use in violence. Specifically, the findings indicate that the substance-use profile of youth-perpetrated homicides particularly has changed markedly over the study period: the dominant context has shifted from situational alcohol consumption to direct or indirect involvement with drugs, and most recently, drug-related homicide profiles accounted for over 40 % of youth-perpetrated homicides. Regarding substance co-use patterns, the findings show that while alcohol-related homicides most often do not involve the co-use of other substances, various drug categories are correlated among homicide offenders, and the co-use of multiple drugs is common among both young and adult drug-involved offenders.