Several methodological issues may affect the findings of studies of the mental health effects of disasters over time. These issues include analysis of the course of individual disorders over time that may be lost when they are presented embedded in general summary statistics, consideration of assessment of psychiatric disorders versus symptoms, adherence to established criteria in assigning psychiatric diagnoses, and orientation of mental health issues to the type of disaster exposure of the sample. This report will explore these methodological issues in a review of disaster literature and in data obtained from study of survivors of the Oklahoma City bombing. Clinical implications of the data obtained from the Oklahoma City bombing study of survivors of the direct bomb blast are presented in the context of these methodological concerns.