Since 2007, the number of people in the U.S. who use the addictive opioid drug heroin has nearly doubled. Not surprisingly, this spike in heroin users has been accompanied by a rise in the number of people who experience heroin overdoses. In a study scheduled for publication in 2014 in the journal Addiction, a team of American and Canadian researchers explored the impact that market factors have on the number of people who receive treatment for a heroin overdose. These researchers found that some market alterations accompany increased rates for overdose, while others do not. Heroin Use The federal Substance Abuse and Mental Health Services Administration (SAMHSA) tracks annual trends in heroin use for American adults and teenagers who are not homeless or incarcerated in a jail or prison. Until 2010, another federal program called the Arrestee Drug Abuse Monitoring Program kept track of heroin use trends among incarcerated men and women. Data from SAMHSA indicates that, among Americans unaffected by homelessness or incarceration, the heroin-using population increased from roughly 373,000 in 2007 to 669,000 in 2012 (the last year with fully available statistics). Information gathered from the final year of the Arrestee Drug Abuse Monitoring Program indicates that the use of heroin may be much more widespread. At the low end, data gathered from these two sources points toward a chronic heroin-using population of about 800,000 individuals. At the high end, the combined data points toward a population of roughly 2.6 million chronic users. In all likelihood, the actual population of chronic heroin users probably hovers around 1.5 million. Heroin Overdose Thousands of people die in the U.S. every year as a result of a heroin overdose. Such an overdose occurs when a person takes enough of the drug to severely slow the rate of nerve cell communication inside the central nervous system (brain and spinal cord), which controls such basic body functions as your heart rate and your involuntary urge to breathe. Some people survive heroin overdoses. However, an affected individual can easily die as a result of breathing stoppage or cardiac arrest (cessation of normal heart function). Doctors can reverse the effects of a heroin overdose with the help of a recently developed medication called naloxone, which essentially stops heroin and other opioid substances from reaching the central nervous system. Unfortunately, many people experiencing an overdose do not receive this medication in a timely manner. Influence of Market Factors In the study slated for publication in Addiction, researchers from the University of Maryland, UC San Francisco and Canada\u2019s Dalhousie University tracked changes in the American heroin market from 1992 to 2008 with the help of figures obtained from the U.S. Drug Enforcement Administration (DEA). For the same period of time, they also tracked annual figures on the number of people who ended up in the hospital in the aftermath of a heroin overdose. The researchers then sought to identify any market factors linked to an increase in overdose cases. Specific factors under consideration included the per-gram price of the drug, the relative purity of available batches of the drug and the region of the world in which the drug was produced. The researchers concluded that both the per-gram price of heroin and the source of heroin production have a significant association with increased rates for heroin overdoses. Every time the per-gram price of the drug falls by $100, the overdose hospitalization rate spikes by about 3 percent. In addition, every time heroin produced in Colombia (or similar to Colombia-produced heroin) gains an additional 10 percent share of the U.S. market, the overdose hospitalization rate spikes by about 4 percent. Interestingly, the researchers concluded that the relative purity of street heroin has no apparent impact on the rate of heroin overdose-related hospitalization in the U.S. The study\u2019s authors began their project, in part, in order to assess certain factors in heroin overdose that might have been overlooked by other researchers. They refer to these factors collectively as the \u201cstructural risk environment\u201d for this type of overdose. The authors concluded that structural change in the heroin market does have an important influence on the country\u2019s overdose rate, even when street-level drug purity is not a major part of the risk equation.