Veterans returning from Afghan and Iraqi combat zones following the 9/11 terror attacks felt the brunt of the opioid epidemic as they acclimatized to civilian life, according to a new study from health economists.

Researchers from the University of Connecticut, University of Georgia, and San Diego State University reported in a study distributed by the National Bureau of Economic Research that combat veterans deployed as part of the global war on terror have an opioid abuse rate about seven times higher than civilians.