['We investigated the relationship between preoperative psychological state and postoperative confusion in elderly drinkers.', 'We studied 81 male patients, ranging in age from 65 to 80 years, who were scheduled to undergo total hip arthroplasty and total knee arthroplasty. The patients were divided into two groups; non-drinkers and patients who drank 25 g or more of alcohol daily. All patients were given a neuropsychological screening evaluation, including a Mini-Mental State test, the Japanese version of the State-Trait Anxiety Inventory (STAI), a depression scale test, and evaluation of a history of aggression and postoperative confusion.', 'Postoperative confusion during the first 72 h after the end of the operation occurred in 7 of the 50 non-drinkers (14%) and in 11 of the 31 drinkers (35%) (P = 0.01). There were no significant differences in STAI (state anxiety and trait anxiety), Mini-Mental State, and depression scale scores between the non-drinkers and drinkers, or between patients with and without postoperative confusion. All 8 patients who had a history of aggression developed postoperative confusion. There was no significant difference in the incidence of postoperative confusion between drinkers who did not have a history of aggression and non-drinkers.'] Is a history of aggression a risk factor for postoperative confusion in elderly male drinkers?