As a doctor, nobody wants to see a reduction in deaths from opioid overdoses more than me. But a condition cannot be treated without making the right diagnosis.

Policymakers in Washington and in state capitals are misdiagnosing the opioid crisis as a doctor-patient problem. Their policies are coming between doctors and patients. They are preventing doctors from using their judgment and expertise to ease pain and suffering. They are making many patients suffer needlessly, with some turning in desperation to the black market.

On Aug. 1 and Sept. 5, two separate raids by combined federal and local narcotics police in New York City seized the largest haul of the powerful opioid fentanyl in New York history. This included 140 pounds of fentanyl (32 million lethal doses), 75 pounds of fentanyl mixed with heroin and additional stores of heroin and cocaine.

New York special narcotics prosecutor Bridget Brennan told reporters, “The sheer volume of fentanyl pouring into the city is shocking. It’s not only killing a record number of people in New York City, but the city is used as a hub of regional distribution for a lethal substance that is taking thousands of lives throughout the Northeast.”

And the New York raid is one of countless other examples in which authorities uncovered evidence of the black market at work and booming.

While raids on black market drug dealers continue to net hauls from a seemingly endless sea of diverted, smuggled or counterfeit prescription opioids and heroin, policymakers can’t shake free of the myth that the opioid crisis is caused by doctors prescribing opioids to their patients in pain.

The numbers show that isn’t the case. The Centers for Disease Control and Prevention reported in July that prescriptions of opioids by health care practitioners have continued their steady decline since 2010. The Drug Enforcement Administration has ordered cutbacks in the production of opioids by pharmaceutical companies.

Since the late 1990s states have established prescription drug monitoring boards that maintain surveillance on providers and patients and have a chilling effect on prescribers. All 50 states have them today.

Researchers at the University of Pennsylvania and Penn State University reported in May prescription drug monitoring boards “were not associated with reductions in drug overdose mortality rates and may be related to increased mortality from illicit drugs and other, unspecified drugs.”

While this full-court-press on doctors and patients continues unabated, the overdose death rate from opioids hit a record high of 33,000 in 2015 — but the majority of deaths were from heroin, and deaths from fentanyl doubled over the previous year.

Reports in the Journal of the American Medical Association and elsewhere tell us the overwhelming majority of overdoses arriving in emergency rooms are not pain patients under medical care.

And if that isn’t enough reason to think policymakers are going after the wrong target, consider three separate studies from the University of Michigan, Johns Hopkins University and the RAND Corp. that show opioid abuse and overdose rates have declined by 25 percent in states where marijuana has been made legally available.

Doctors know when a therapeutic regimen is not working — or may be making matters worse. We’re open to rethinking our diagnosis. It is time for policymakers to learn to do the same.

Jeffrey A. Singer practices general surgery in Phoenix and is a senior fellow at the Cato Institute. He wrote this for The opinions are the writer's.