"We detected no reduction in druguse frequency or drug price in response to a large-scale police crackdown on drug users in Vancouver's DTES. The evidence that drugs became more difficult to obtain was consistent with reports of displacement of drug dealers and was supported by the significantly higher rates of reporting that police presence had affected where drugs were used, including changes in neighbourhood and increases in use in public places. These observations were validated by examination of needle-exchange statistics.
"Our findings are consistent with those showing that demand for illicit drugs enables the illicit drug market to adapt to and overcome enforcement-related constraints. Although evidence suggested that police presence made it more difficult to obtain drugs, this appeared to be explained by displacement of drug dealers."
Wood, Evan, Patricia M. Spittal, Will Small, Thomas Kerr, Kathy Li, Robert S. Hogg, Mark W. Tyndall, Julio S.G. Montaner, Martin T. Schechter, "Displacement of Canada's Largest Public Illicit Drug Market In Response To A Police Crackdown," Canadian Medical Association Journal, May 11, 2004: 170(10), p. 1554.