The number of children hospitalized as a result of opioid overdose has nearly doubled since 2004, a new report published Monday in Pediatrics concludes.
The study considered the records of children age one to 17, CNN reports, and found 1,504 opioid overdose admission between 2012 and 2015, an almost doubling from the 797 between 2004 and 2007.
43 percent of the cases identified by the study's authors ended up in the pediatric intensive care unit, usually reserved for the most severe, life-threatening cases.
Over the 11-year period they studied, the researchers identified 3,647 opioid-related patients in 31 children's hospitals across the United States.
According to study author Dr. Jason Kane, those child overdoses fell into two categories: teenagers taking drugs for recreational or self-harming purposes, and younger children who accidentally consumed their parents' opioid medication. Those age 12 to 17 made up 60 percent of opioid overdose admissions; the second-largest group was between one and five years old.
Kane noted one particularly concerning trend: the younger children were frequently overdosing on methadone.
Methadone, an opioid which does not induce the same adverse withdrawal symptoms as forms like heroin and fentanyl, is used to wean opioid addicts off of their drug of choice through so-called methadone maintenance. It can also be used as a prescription painkiller.
"The thing that was a bit striking is that in the youngest children, those under six years of age, 20% of the ingestions were of methadone. So you sort of have to ask yourself: where are they getting all this methadone from?" Kane told CNN.
These accidental overdoses on parents' medication are just one example of how children can become what Kane called "secondary victims" of America's opioid epidemic, which claimed over 42,000 American lives in 2016.
"Children accidentally getting into medications is not a new phenomenon," Kane told CNN. "But this is probably a reflection of the massive amount of drugs—opioid drugs—that are available to children in the community."
There was at least one positive trend reflected in the study—mortality for minors admitted for opioid overdoses has declined. It dropped to 1.3 percent in the 2012 to 2015 period, down from 2.8 percent in the 2004 to 2007 period.
This trend among children is the opposite of opioid mortality in hospitals for the nation overall. A recent study found that deaths from opioid-driven hospitalizations quadrupled between 2000 and 2014, doubling between 2000 and 2007, then doubling again between 2007 and 2014. Today, drug overdose has outpaced car crashes, suicide, and homicide to become the number one cause of injury death in the United States.