The use of opioids is linked to the unemployment rate, a paper published in the National Bureau of Economic Research. Researchers, who are working on the paper Macroeconomic Conditions and Opioid Abuse, analyzed the connection between drug deaths and the economic climate for their study.

The research comes as the number of opioid-related overdose deaths, which includes prescription opioids such as oxycodone, hydrocodone, and methadone, as well as heroin have quadrupled since 1999, according to the Centers for Disease Control and Prevention.

“The fact that some of the recent rise in drug deaths coincides with the Great Recession and its aftermath highlights the importance of understanding the connection between economic conditions and drug deaths,” the researchers, Alex Hollingsworth, Christopher Ruhm, and Kosali Simon, wrote in the paper.

Although the unemployment rate is currently at a record low of 4.3 percent, the paper shows those who don’t have jobs aren't kept out of the spotlight as the country battles the opioid crisis.

Researchers looked at the how deaths and emergency department visits caused by opioids and other drugs correlated with the local unemployment rate.

When the unemployment rate in a county increases by one percentage point, the opioid-related death rate per 100,000 jumps by 0.19 (3.6 percent), while the opioid emergency department visit rate per 100,000 rose by 0.95 (7.0 percent), the paper said. The estimated impacts are larger when researchers use unemployment rates based by state, rather than counties.

"Overall, we obtain strong evidence that opioid-related deaths and ED visits increase during times of economic weakness," the researchers said.

They wrote:

"[…] notwithstanding the possible pathways just described, we suspect that the dominant factor linking macroeconomic conditions to adverse drug outcomes is that the fatal and near fatal abuse of opioids often (and increasingly over time) reflects a physical manifestation of mental health problems that have long been known to rise during periods of economic decline... With the increased availability of prescription opioids (and reductions in heroin prices), it seems likely that the consumption of these drugs rises when economic conditions worsen and that some of this increased use leads to adverse outcomes including ED visits or death."

Last month, Federal Reserve Chair Janet Yellen was asked in a testimony before the Senate Banking Committee about opioid deaths’ link to the job market.

"I do think it is related to declining labor force participation among prime-age workers," she said. "I don’t know if it's causal or if it's a symptom of long-running economic maladies that have affected these communities and particularly affected workers who have seen their job opportunities decline."

The data used by researchers were from the CDC’s Multiple Cause of Deaths files between 1999 to 2014. However, one of the researchers, Ruhm, previously worked on another study that found the number of opioid deaths might actually be higher, since the number of opioid and heroin deaths are calculated through death certificates which sometimes do not specify which drug was used during a fatal overdose. T

The study found opioid deaths across the country were 24 percent higher than reported rates, while heroin fatalities were 22 percent greater.