A number of factors intervene in the process that leads to the commission of homicide. For example, the availability of a weapon: with their high level of lethality, firearms are the most widely used weapons, accounting for 4 out of every 10 homicides at the global level. The use of psychoactive substances may act as homicide "enablers": the consumption of alcohol and/or illicit drugs increases one's risk of becoming a victim or perpetrator of violence. As well as violence associated with the consumption of illicit drugs, violence associated with the functioning of illicit drug markets can also drive homicide levels, often due to competition between involved parties. Such elements can shape patterns and levels of homicide, and when they are targeted by prevention policies, homicide can be reduced.
In this chapter: