Chapter 14 of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) discusses diagnosis, mental impairment, impairment severity assessment, special impairment categories, report format, and psychiatric impairment evaluation. The chapter differs from others in the AMA Guides insofar as it does not provide percentages for estimates of mental impairment because such usage suggests a certainty that does not exist. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, is a widely accepted classification system for mental disorders, but it omits context. Few clinically standardized tests can identify functional or structural effects, and neuropsychological testing is not the standard for documenting subtle impairment. How individuals manage their illness and cope with life demands are better measures of impairment than diagnostic labels or numbers and kinds of symptoms. Further, assessment requires an evaluation of the context in which the illness unfolds, including premorbid function and previous response to treatment; details about the individual's life course; review of developmental and functional deficits; character style and comorbidities such as anxiety and substance abuse; severity of precipitants, current stage of the episode, and current effectiveness of treatment; and external supports that can moderate impairment. A table lists areas of functional impairment, symptoms to consider, and patient history relevant to symptoms.