The price of cocaine, heroin and marijuana have fallen over the last two decades while the purity and potency of these illegal drugs have risen, according to new research.
In a paper published online recently in the journal BMJ Open, researchers say a review of drug surveillance databases suggests that global efforts to combat illegal drugs have failed to curb supply.
After reviewing online drug surveillance databases for governments across the globe, researchers said they documented a clear drop in the price of illegal drugs in major drug consuming nations, as well as a trend toward larger drug seizures by authorities.
These trends, combined with increased drug potency, suggested that "the global supply of illicit drugs has likely not been reduced in the previous two decades," wrote lead author Dan Werb, an epidemiologist at Canada's British Columbia Centre for Excellence in HIV/AIDS.
"It is hoped that this study highlights the need to re-examine the effectiveness of national and international drug strategies that place a disproportionate emphasis on supply reduction at the expense of evidence-based prevention and treatment of problematic illegal drug use," Werb and his colleagues wrote.
The United Nations has estimated that the global illicit drug trade is worth at least $350 billion a year. In addition to the harm associated with drug use, narcotics are also a key factor in the transmission of blood-borne diseases like HIV, the authors wrote.
According to study authors, the average inflation-adjusted prices of heroin, cocaine and cannabis in the United States decreased by 81%, 80% and 86%, respectively, between 1990 and 2007. At the same time, their average purity increased by 60%, 11% and 161%, respectively, authors wrote.
Meanwhile, U.S. seizures of cocaine fell by roughly half between 1990 and 2010, while those of marijuana and heroin rose 465% and 29%, respectively.
Study authors said they observed similar trends in Europe, where the price of opiates and cocaine decreased by 74% and 51%, respectively. Seizures for cocaine and cannabis fluctuated, but heroin seizures rose 380% by 2009.
Researchers acknowledged that their study had limitations. It did not include amphetamine-type stimulants and other new synthetic drugs and was limited to certain regions. Also, researchers said that price and purity of illegal drugs were not the only indicators of drug availability and that future studies should include other measures, such as street-level questionnaires given to drug users.
To listen to a BMJ Open podcast on this study click here.