For years, people who used drugs were treated like criminals, often given long sentences. Now there's growing acceptance that addiction is a treatable disease, but shame and discrimination linger.

Researchers know how to curb the risks of overdose and disease among drug users, but policymakers are reluctant to allow public health measures that include needle exchanges and access to safer drugs.

President Nixon called for an "all-out offensive" against drugs and addiction. The U.S. is now rethinking policies that led to mass incarceration and shattered families while drug deaths kept rising.