ANN ARBOR, MI - Fifty-one percent of all opioid medications distributed in the United States each year are prescribed to adults with mood disorders such as depression and anxiety, new research from the University of Michigan and the Geisel School of Medicine at Dartmouth shows.
"Despite representing only 16 percent of the adult population, adults with mental health disorders receive more than half of all opioid prescriptions distributed each year in the United States," said Matthew Davis, lead author of the study and assistant professor at UM's School of Nursing.
Overall, of the 115 million prescriptions written for opiates each year, 60 million are written for adults with mental illness.
Davis said opioid use by patients with mental health disorders identified in the research were for a wide variety of different co-existing conditions. Most of the reasons for opioid use were for other pain-related conditions the individuals also suffered from.
"The relationship between pain and mental health is complex and interrelated," Davis said in an email.
"Opioids should not be prescribed for mental health conditions specifically," he added. "However, adults with mental health conditions were more likely to get opioids at varying levels of pain. For instance if you take two patients in severe pain - one with depression and one without - the one with depression was more likely to end up on an opioid."
In Michigan, health-care providers wrote 11 million prescriptions for opioid drugs in 2015 and another 11 million in 2016 - enough to provide every Michigan resident with his or her own bottle of narcotics, according to state data. That compares to roughly 8 million prescriptions in 2009.
Opioids are a class of drugs that include the illegal drug heroin, synthetic opioids such as fentanyl and prescription pain relievers such as OxyContin, Vicodin and codeine.
The study, "Prescription opioid use among adults with mental health disorders in the United States," is among the first to show the extent to which the population of Americans with mental illness use opioids. It is expected to be published online July 6 in the Journal of the American Board of Family Medicine.
Researchers found that among the 38.6 million Americans diagnosed with mental health disorders, more than 7 million - or 18 percent - are prescribed opioids each year. By comparison, only 5 percent of adults without mental disorders are likely to use prescription opioids.
In Michigan, prescription opioids account for more than twice as many overdose deaths as heroin, although many addicts get their prescription painkillers illegally. In 2015, Michigan saw 884 overdose deaths due to prescription opioids, compared to 391 heroin overdose deaths.