A federally funded report released last week came to a striking conclusion: More than 80 percent of the roughly two million people struggling with opioid addiction in the United States are not being treated with the medications most likely to nudge them into remission or prevent them from overdosing. This denial of care is so pervasive and egregious, the report’s authors found, that it amounts to a serious ethical breach on the part of both health care providers and the criminal justice system.

The Food and Drug Administration has approved three medications to treat opioid use disorder — methadone, buprenorphine and naltrexone. All of them work by binding to the brain’s opiate receptors in a way that reduces the cravings that people addicted to drugs like OxyContin and heroin experience, but without causing the same euphoric high as those drugs. Methadone and buprenorphine have proved especially effective. Patients who take one of those medications are half as likely to die from their addiction; they are also more likely to stay in treatment, and they tend to have better long-term health outcomes.

Neither drug is new or experimental — methadone was approved to treat opioid addiction in 1972 and buprenorphine in 2002. Some countries have shown that increasing access to them can significantly drive down the rate of overdose deaths. In France, for example, policies that enabled more doctors to prescribe buprenorphine helped lead to a tenfold increase in the number of people whose opioid use disorder was being treated and to a nearly 80 percent decline in overdose deaths in just four years.

Yet, many drug courts and most residential treatment programs in the United States prevent participants from using these medications; and the rehabilitation programs that do offer them rarely offer all three options. The treatments are not available in most emergency rooms, as The Times has reported, even though studies show that patients given buprenorphine in an E.R. are twice as likely to be in treatment a month later than those who are given an information pamphlet. They are also not available in most prisons, even though a significant portion of the federal inmate population suffers from opioid use disorder. Opioid overdose is a leading cause of death among those who’ve been recently released.