With the opioid epidemic in full swing, a new study has revealed one in six people in the U.S. are taking some form of psychiatric drug in order to treat depression, anxiety and insomnia.

Data from the Medical Expenditure Panel Survey from 2013 was used to calculate the percentage of adults who were using prescription drugs such as anti-depressants and anti-anxiety solutions. Co-author of the research, Thomas Moore and his colleague, Donald R. Mattison of Risk Sciences International in Ottawa, found nearly 17 percent of adults received a prescription for drugs such as Zoloft, Xanax and Ambien.

“From a drug safety perspective, I am concerned that so many of these drugs have withdrawal effects and that some of the overwhelming long-term use may reflect drug dependence,” said Moore. “These questions need further investigation.”

Within the survey, they found one in five women has filled out a prescription – around twice as many as men. Whites were also twice as likely to have taken a prescription drug than blacks or Hispanics.

Moore and his colleague was more concerned about long-term use and the problem of dependency and withdrawal effects especially as usage rates were higher with increased age. The survey also revealed that around 85 percent of those that filled out a prescription for a drug in 2013 continued with more prescriptions throughout the entire year showing prolonged use.

“To discover that eight in 10 adults who have taken psychiatric drugs are using them long term raises safety concerns, given that there’s reason to believe some of this continued use is due to dependence and withdrawal symptoms,” stated Moore.

The study has raised concerns about fully educating primary care doctors who prescribe psychiatric drugs and monitoring long-term mental conditions with health screenings at annual checkups.

Details of the research were published in the journal JAMA Internal Medicine.