This chapter discusses the prevalence and correlates of trauma-related mental disorders as well as on initial patterns of treatment of Hurricane Katrina disorders. It examines associations of the mental health and treatment outcomes with a number of sociodemographic variables. Mental disorders were estimated with screening scales rather than with clinical interviews, although calibration was used to select clinical cut-points on the screening scales. The assessment of disaster-related stressors was necessarily retrospective, raising concerns about recall bias related to mental illness at the time of interview and the possibility that the associations between stressors and mental disorders were overestimated. The comparison of results from the first wave of the Community Advisory Group (CAG) survey with results from the National Comorbidity Survey-Replication (NCS-R) was an inexact way to estimate the initial mental health effects of Hurricane Katrina due to the fact that the NCS-R and the CAG surveys differed in many ways.