The data presented here indicate that the record seizure of heroin in autumn 2000 appeared to have no impact on injection use of heroin or on perceived availability of heroin. Furthermore, we detected no difference in the extent to which drug users reported that enforcement had affected their drug source, the types of drugs available or their pattern of drug use.
Several factors may explain our observations. First, we must accept the possibility that the results can be explained by chance or confounding factors. Although we detected no evidence of a significant difference between the 2 study groups, it is possible that unmeasured confounding persisted. In addition, we recognize that the reduction in the price of heroin that we observed was probably due to random fluctuation or compensatory shipments and was not causally connected to the seizure. With regard to the possibility that compensatory shipments explain our findings, previous studies have found that heroin seizures tend to correlate with times of high production and supply of drugs.18,19
We do not believe that interview bias played a role because the interviews were not conducted to assess the effect of the seizure but rather constituted the data instrument for an ongoing HIV incidence study; thus the interviewers and participants were in effect “blind” to this eventual use of the data. We should also note that although 148 (56.7%) of those considered in the present analyses were active heroin injectors, only 75 (28.7%) injected heroin daily. Nevertheless, the results were unaffected when we restricted the analysis to current heroin users (data not shown).
It could be argued that a 30-day period after the seizure was insufficient to capture a reduction in supply due to the seizure. To address this possibility, we conducted additional analyses and detected no difference when we examined data for a full 12 weeks after the seizure. It could also be argued that the heroin shipment was never intended for the local market. Although the inability to determine with certainty the final destination of the heroin is a limitation of the present study, the circumstances of the seizure suggest that the heroin was destined for the Vancouver market. Specifically, the seizure was the result of a 20-month investigation by the Vancouver Royal Canadian Mounted Police Asian Organized Crime Unit, which led to the arrest of several Vancouver men. During the investigation, information was acquired that led officials to conclude that the heroin was destined for the local market.9,12,13
Nevertheless, had the heroin been destined for shipment away from the market created by the area's estimated 5000 to 10 000 injection drug users,5
this would suggest that the local market was already saturated.16,17
Finally, it could be argued that the seizure led suppliers to reduce the purity of the heroin they sold so as to maintain the quantity of drug available. However, participants reported no difference in their source of drugs or the type of drugs available, and we found no decreases in overdoses or heroin use, nor any change in methadone use when the 12-week post-seizure period was examined (). All of these variables have previously been associated with fluctuations in the purity of street-level heroin.20,21,22
Externally compiled data appear to support our findings. Specifically, there were 10 fatal overdose deaths in the month before the seizure, whereas there was an average of 13.3 overdose deaths per month during the 3 months after the seizure (monthly illicit drug overdose statistics for 2000; BC Coroner Service, unpublished data). In addition, data from Health Canada's Drug Analysis Services, a group that often tests the purity of heroin samples provided by police, showed no decrease in the purity of heroin samples tested during the 3-month periods before and after the seizure (Health Canada, Drug Analysis Services, Burnaby, BC, unpublished data).
Analyses conducted by the United Nations Office for Drug Control and Crime Prevention suggest that a maximum of 5% of the global illegal drug flow is seized by law enforcement agencies.19
For this reason, despite the expenditure of tens of billions of dollars annually on drug interdiction efforts in North America,7
heroin purity has increased and prices have markedly decreased since the late 1980s.8,21
In turn, high HIV incidence rates have persisted, and overdose is among the leading cause of death in many large Canadian and US cities.3,4,23,24
In Baltimore, for example, overdose deaths increased by more than 425% between 1990 and 1997.24
In the present study we observed no beneficial public health effects of Canada's largest-ever heroin seizure. In our view, the most plausible explanation is that the seizure had no significant effect on the supply of heroin in this locality.25
This conclusion is supported by a recent report by the World Customs Organization, which found that even post-September 11 security measures have had a “negligible” impact on the influx of illicit drugs into the US. Given the size of the seizure relative to other large heroin seizures,10,11
our findings raise serious questions about the potential for Canada's present drug policies to adequately control the drug use epidemic through supply-side interventions. It is critical to emphasize our view that fault does not lie with the front-line law enforcement officers who are involved in supply-side strategies at the operational level. Rather, the responsibility lies with the politicians and policy-makers who continue to direct the overwhelming majority of resources into failing supply-reduction strategies, despite the wealth of scientific evidence demonstrating their ineffectiveness.6,26,27,28
Our findings support the strong consensus that curbing the HIV and overdose epidemics will require a shift in emphasis toward alternative strategies based on prevention, treatment and harm reduction, even if this shift necessitates a diversion of resources away from criminal justice interventions.5,26,27,28,29,30