Barack Obama drew a clear line between prescribing trends and America's opioid epidemic on Thursday. The president recognized that the increased availability of prescription painkillers has fueled the public health crisis in an article published in the Harvard Law Review.

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"Since 1999, sales of prescription opioid pain medications have quadrupled," Obama wrote. "In 2012, 259 million prescriptions were written for these drugs, which is more than enough to give every American adult their own bottle of pills."

But the epidemic doesn't stop at painkillers, he continued, noting the "dramatic rise in the use of heroin" and the fact that "four in five new heroin users started out by misusing prescription drugs and then transitioned to heroin."

Public health experts have demonstrated how long-term use of prescription painkillers can create physical dependency in patients that ultimately leads to addiction. If a patient's supply runs out, or the cost of the prescription becomes too expensive, some turn to cheaper and more potent opioids such as heroin. Over the past 10 years, the problem has metastasized throughout the country, contributing to record-high overdose deaths.

Obama reflected on his administration's efforts to curb the epidemic, which included measures meant to enhance regulations of opioid-based painkillers. He explained how the U.S. Department of Justice has been "targeting heroin and prescription opioid traffickers and the illegal opioid supply chain" while also cracking down on clinics that irresponsibly dispense painkillers for profit, known as "pill mills."

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Though he stopped short of calling out the pharmaceutical industry for its role in the crisis — as some Democratic lawmakers such as Sen. Bernie Sanders have in the past — the Obama's emphasis on prescribing trends seem to represent a break from his previous statements on the issue. However, his recent comments has left little room for debate over the origins of the crisis.

Ultimately, the solution to the problem involves recognizing that "the opioid epidemic is a public health problem that requires a public health response" and to place the policy focus on treatment over punishment," Obama wrote. "Now the crucial next step is putting those resources to work so that every American who wants treatment can get it and start on the road to recovery."