“Doctors believed that pain was salutary,” she tells Fresh Air‘s Terry Gross, “meaning that it had some physiologic benefit to the individual, and certainly some spiritual benefit.”

But as prescription painkillers became more available, patients became less willing to endure pain. Suddenly, Lembke says, “doctors began to feel that pain was something they had to eliminate at all cost.”

Prescriptions for opioid painkillers increased, and so, too, did cases of opioid addiction. In 2011, the Centers for Disease Control and Prevention declared a prescription drug epidemic as a result of doctors overprescribing painkillers to patients. Lembke’s new book, Drug Dealer, MD, explores the origins of the prescription drug epidemic from a doctor’s perspective.

“Starting in the 1980s, doctors started to be told that opioids were effective treatment for chronic pain, and that treating patients long-term with opioids was evidence-based medicine,” she says. “That was patently false and that was propagated by what I call ‘big medicine,’ in cahoots with Big Pharma.”