Rates of deaths involving opioids, specifically heroin and synthetic opioids, the latter probably driven primarily by illicit fentanyl, have increased considerably across the United States. Available at Available at www.cdc.gov/nchs/health_ policy/mortality.htm. While heroin use has remained high among men, the rate of increase of heroin use among women has been higher than among men: between 2002 and 2004, the average rate of past-year heroin use was 2.4 per 1,000 men and 0.8 per 1,000 women, whereas between 2013 and 2015, the rate of past-year heroin use increased to 4.3 per 1,000 men and 2.0 per 1,000 women. As the progression to addiction to opioids may be accelerated among women, the development of addiction among women following treatment with opioids for a legitimate medical condition (iatrogenic addiction) may explain the comparable levels of misuse of prescription opioids among the sexes.3 In 2015,4 per cent of women, compared with 5.3 per cent of men, had misused prescription opioids in the previous year.