Drug market disruption and systemic violence: Cannabis markets in Copenhagen

This study aims to examine the association between drug law enforcement and rates of serious violence. A police crackdown on a large and stable cannabis market in Copenhagen disrupted established hierarchies among criminal groups and spurred renewed competition. In the five-year period after the crackdown in 2004 there were more homicides and attempted homicides in Denmark than in any five-year period for the previous 20 years. In the Copenhagen region we found 19 shootings that had a connection to known cannabis sellers or cannabis-selling locations. No such episodes were known prior to the crackdown. We estimate a fixed-effects (within) regression model for all Danish municipalities for the period 2000–9 (N = 2110, 269 groups). We find that there has been a significant relationship (p = .001) between drug arrests and charges for serious violence the following year, after correcting for demographic and social covariates found to be correlated with violence.