New York: Non-medical use of prescription opioids more than doubled among adults in the US from 2001-2002 to 2012-2013, new research has found. The findings are based on a study from the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health which is part of the US Department of Health and Human Services. The study found that nonmedical prescription opioid use among US adults has increased by 161 percent from 2001-2002 to 2012-2013 while prescription opioid use disorder has increased by 125 percent during the same period. Nearly 10 million Americans, or 4.1 percent of the adult population, used opioid medications in 2012-2013 a class of drugs that includes pain relievers OxyContin and Vicodin, without a prescription or not as prescribed -- in greater amounts, more often, or longer than prescribed. This is up from 1.8 percent of the adult population in 2001-2002. More than 11 percent of Americans report nonmedical use of prescription opioids at some point in their lives, a considerable increase from 4.7 percent ten years prior, the findings showed. "The increasing misuse of prescription opioid pain relievers poses a myriad of serious public health consequences," said Nora Volkow, Director of National Institute on Drug Abuse (NIDA), which contributed funding for the study. "These include increases in opioid use disorders and related fatalities from overdoses, as well as the rising incidence of newborns who experience neonatal abstinence syndrome. In some instances, prescription opioid misuse can progress to intravenous heroin use with consequent increases in risk for HIV, hepatitis C and other infections among individuals sharing needles," Volkow pointed out. Scientists analysed data from National Institute on Alcohol Abuse and Alcoholism's National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III), ongoing research that examines alcohol and drug use disorders among the US population, as well as associated mental health conditions. The findings appeared online in the Journal of Clinical Psychiatry. The authors suggest that the rise in prescription opioid misuse may be due in part to increase in opioid prescribing and dosage, lessened perception of risk because of its legality, and lack of understanding of addictive potential. Prescription opioid misuse is an urgent public health problem, with drug poisoning deaths involving opioid analgesics, which includes both prescription and illicit opioids, quadrupling between 1999 and 2014, according to the US Centers for Disease Control and Prevention (CDC).