“…Two studies included data from emergency department (ED) visits and hospitalizations for overdose but did not specify whether the overdoses were fatal or not [61,62]. Most studies either did not report intention of overdose (n = 17) [15, 33, 35, 39-41, 46, 48, 51-53, 58, 59, 61-64] or examined both intentional and unintentional overdose (n = 17) [30-32, 36-38, 42-45, 47, 49, 54-57, 60] with four examining only unintentional overdose [28,29,34,50]. Many studies (n = 20) included overdose that was attributable to prescription and non-prescription opioids [29, 32, 35-37, 41-47, 49, 50, 56-58, 60, 63, 64], while eleven investigated only prescription opioid overdoses [28, 33, 34, 38, 48, 51-54, 61, 62] and two investigated only non-prescription opioid overdoses [15,39].…”