Judgments about people with pain are influenced by contextual factors that can lead to stigmatization of patients who present in certain ways. Misplaced staff perceptions of addiction may contribute to this, because certain pain behaviors superficially resemble symptoms of analgesic addiction. We used a vignette study to examine hospital staff judgments about patients with genuine symptoms of analgesic addiction and those with pain behaviors that merely resemble those symptoms. Nurses and doctors at hospitals in London, UK, judged the level of pain, the likelihood of addiction, and the analgesic needs of fictitious sickle cell disease patients. The patient descriptions included systematic variations to test the effects of genuine addiction, pain behaviors resembling addiction, and disputes with staff, which all significantly increased estimates of addiction likelihood and significantly decreased estimates of analgesic needs. Participants differentiated genuine addiction from pain behaviors resembling addiction when making judgments about addiction likelihood but not when making judgments about analgesic needs. The treatment by staff of certain pain behaviors as symptoms of analgesic addiction is therefore a likely contributory cause of inadequate or problematic hospital pain management. The findings also show what a complex task it is for hospital staff to make sensitive judgments that incorporate multiple aspects of patients and their pain. There are implications for staff training, patient education, and further research.