Distress and professional impairment among psychotherapists are important to address tiff a number of reasons, including the impact of impairment on therapeutic effectiveness and on the reputation of the field of psychology. The focus of this review is on one type of impairment, namely the mental health difficulties of applied psychologists. Following a brief discussion of the history of impairment, definitional issues are examined. A review and critique of the prevalence data on distress and impairment among psychologists are presented. Relevant research supporting the three causal factors of impairment outlined by Guy (1987) are discussed, followed by an examination of the various factors that allow for the continuation of impairment. Finally, prevention efforts are reviewed, with suggestions for additional preventive endeavors that could be beneficial.