Most painkiller use isn't misuse, which SAMHSA defines as any use of painkillers in a manner not directed by a doctor. This can include taking painkillers without a prescription for the purpose of getting high, or taking the drugs for a longer period of time or at a higher quantity than recommended by a doctor.
Indeed, part of painkillers' prevalence owes to how effective they are, and to the difference they can make in the lives of pain sufferers. It's hard to imagine recovering from an invasive surgery without having something to treat the residual pain, for instance. And for many people afflicted with chronic pain, proper management with prescription painkillers can mean the difference between debilitating illness and daily functioning.
But many prescription painkillers are highly habit-forming, and they can be deadly if taken at high doses, or in conjunction with other drugs such as alcohol. In 2014, according to the Centers for Disease Control and Prevention, opioid painkillers killed nearly 19,000 Americans. That's greater than the total number of Americans (15,809) who were murdered that year.
Those numbers are so high partly because Americans have developed a voracious appetite for painkillers in recent years. A 2008 study estimated that Americans consume about 80 percent of the global opioid supply and 99 percent of the supply of hydrocodone, one of the most popular prescription painkillers.
A recent investigation by the Center for Public Integrity and the Associated Press detailed the intense lobbying efforts pharmaceutical companies have made to keep these drugs lightly regulated and readily available. The investigation found that when it comes to lobbying, pro-painkiller groups outspend groups arguing for tighter restrictions by more than 200 to 1.
There are examples of pharmaceutical companies engaging in unscrupulous or illegal behavior to promote opioid drugs. In 2007 Purdue Pharma, maker of Oxycontin, pleaded guilty to charges that it misled regulators and doctors about the abuse potential of the drug.
More recently, employees at Insys Therapeutics, a manufacturer of the powerful painkiller fentanyl, plead guilty to charges involving kickback schemes for fentanyl sales. The company remains the target of numerous state and federal investigations.
SAMHSA's latest numbers indicate that painkillers are still widespread despite recent federal efforts to impose tighter restrictions on their prescription and use. It's unclear whether the 38 percent of adults using painkillers last year represents an increase or a decrease over previous years, because SAMHSA only recently added a battery of detailed prescription drug use questions to its annual National Survey on Drug Use and Health.
Reducing the scope of the opioid epidemic has been a priority for President Obama. Earlier this year the White House requested $1.1 billion from Congress for fighting opioid addiction.
But critics have argued that Drug Enforcement Administration policies -- some long-standing, some new -- are undercutting federal efforts to curb opioid abuse.
For instance, earlier this year, the DEA refused to reduce restrictions on marijuana use, arguing that there was insufficient evidence of marijuana's medical benefits. Multiple studies have found that access to medical marijuana is associated with reductions in prescription painkiller abuse and overdose rates.
More recently, the DEA announced a plan to ban the use of kratom, a Southeast Asian plant with opiate-like qualities. Many users of kratom report that the plant has helped them quit using more powerful prescription painkillers. Researchers are worried that without kratom available to them, these users will return to prescription painkillers or move on to heroin.