Background: This study aims to define incidence and risk factors of both emergence agitation and hypoactive emergence in adult patients and substance dependent patients following general anesthesia to elaborate the risk factors and precise management of them.Methods: 1136 adult patients underwent elective surgeries under general anesthesia were recruited in this prospective observational study. Inadequate emergence was determined according to the Richmond Agitation-Sedation Scale (RASS). Emergence agitation was defined as a RASS≥ +1 point, and hypoactive emergence was defined as a RASS≤ -2 points. Subgroup analyses were then conducted on patients with substance dependence.Results: Inadequate emergence in the PACU occurred in 20.3% patients including 13.9% patients with emergence agitation and 6.4% patients with hypoactive emergence. There were 95 patients with a history of substance dependence. The single and married patients undergoing gynecological and thoracic surgeries had a lower risk of agitation compared to the divorced patients. Neurologic disorders, intraoperative blood loss, intraoperative morphine, and analgesic drugs administration in PACU were associated with increased risk of agitation. Hypertension and psychological disorders, intraoperative opioids and Foley catheter fixation in PACU were associated with increased risk of hypoactive emergence. Substance dependent patients were at a higher risk for agitation (21.1%, P = 0.019) and hypoactive emergence (10.5%, P = 0.044). Conclusions:Inadequate emergence in PACU following general anesthesia is a significant problem that is correlated with several perioperative factors. It seems that patients with a history of substance dependence are more at the risk of inadequate emergence than normal population. This article is