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What caused the opioid crisis?
An opioid crisis gripped the U.S. long before President Trump declared it a public health emergency late last year.
Deaths from opioids have quadrupled since 1999, killing more than 42,000 people in 2016, according to the Centers for Disease Control and Prevention (CDC).
The opioid epidemic is now considered to be the deadliest drug overdose crisis in American history, and it is the driving force behind drug overdoses now being the leading cause of death for Americans under 50.
How did this begin?
It began in the late 1990s, when doctors and health care providers started facing pressure to treat chronic pain more aggressively.
Advocates began encouraging doctors to treat pain as a "fifth vital sign" and recommended the long-term use of opioids - such as OxyContin - for all chronic pain.
At the same time, pharmaceutical companies began marketing these drugs to medical providers as not addictive or harmful.
As a result, doctors began prescribing them at greater rates. According to the CDC, by 2015, enough pills were being prescribed to medicate every American around the clock for three straight weeks.
But opioids are highly addictive, and studies show that patients given longer-lasting prescriptions, such as a week or a month, were most likely to become addicted.
Opioids increasingly were misused by the people they were prescribed to. Plus, about half of those who misused prescription opioids obtained the drugs from family and friends without a prescription, according to the National Survey on Drug Use and Health.
Doctors have also come under fire for overprescribing: either by writing a prescription when it wasn't necessary or by writing prescriptions that covered a weeks-long supply when a few pills would be enough.
Why did this become a crisis?
Over time, prescription opioids became harder to get legally, mostly because of efforts to crackdown on excessive prescribing and enhanced law enforcement efforts. Looking for alternatives, or cheaper options, some turned to heroin or black market fentanyl.
Fentanyl is a power anesthetic - 30 to 50 times more potent than heroin and 50 to 100 times more potent than morphine - used by patients to relieve severe chronic pain.
Over the past few years, however, it has been manufactured illicitly and sold on the streets.
From 2010 to 2015, annual overdose deaths involving opioids increased nearly 57 percent, largely due to the spike in use of fentanyl and other synthetic opioids.
Of the 42,000 opioid overdose deaths in 2016, 19,400 were linked to synthetic opioids, making those the deadliest opioids for the first time.
Nearly 80 percent of Americans now using heroin reported misusing prescription opioids first, although only a small fraction of people who use pain pills switch to heroin.
In response, there's been a recent push for access to addiction treatment, including medication-assisted treatment like methadone and buprenorphine.
How has the federal government responded?
The Comprehensive Addiction and Recovery Act (CARA) passed in 2016 was the most expensive federal legislation to date for addiction support services, and designated $80 million toward advancing and improving access to treatment and recovery support services across the country.
A bipartisan group of senators are hoping to follow that up with CARA 2.0, which would establish a three-day initial prescribing limit on opioids for acute pain. It aims to increase the availability of treatment as well as put more money toward the epidemic.
On the House side, Energy and Commerce Committee Chairman Greg Walden (R-Ore.) hopes to pass by Memorial Day weekend eight enforcement and patient safety bills aimed at fighting the epidemic, including one that would give the Drug Enforcement Administration power to stem the tide of fentanyl.
The two-year budget deal Congress passed earlier this year included $6 billion in funding to deal with the crisis this year and next year.
Late last year, President Trump declared the crisis a public health emergency and his 2019 budget proposal includes $17 billion to address the epidemic.