OBJECTIVE This article provides an overview of what is known about "difficult patients" in mental health care. It aims to answer three main questions: What are the defining characteristics of difficult patients, how is the difficulty explained, and which treatment strategies are available? METHODS A search of the MEDLINE, PsycINFO, and CINAHL databases was conducted for articles published between 1979 and 2004 that had "difficult patients" as their main topic, resulting in 94 eligible articles. RESULTS Characteristics of difficult patients in psychiatric care were consistent across several studies. Explanations for these difficulties widely varied: individual, interpersonal, and social factors were identified. Interventions were described in little detail and offered relatively few specific guidelines for daily practice, although some general principles are summarized. Difficult patients are classified into three subgroups, and some prevailing discourses on difficult patients in mental health care are discussed. CONCLUSIONS Treatment strategies or settings exist for two of the three groups of difficult patients-those with severe mental illness (unwilling care avoiders) and those with the least severe psychiatric symptoms but the most difficult behaviors (demanding care claimers). The remaining group (ambivalent care seekers), which consists of those who seek care but exhibit ambivalent behaviors that could be interpreted as both difficult and ill, is not supported sufficiently by effective treatment strategies. Further development and research into effective interventions is suggested for this group.