The first analysis found that in the areas hit by Hurricanes Katrina and Rita, the rate of past month marijuana use among adults 18 years old or older was lower in the year following the hurricanes than in the year before the hurricanes. There were no significant differences in the prevalence of illicit drug use, binge alcohol use, cigarette use, mental health problems, mental health treatment, or unmet needs for mental health treatment in the same period. The second analysis found that adults 18 years old or older who were displaced from their homes for 2 or more weeks following the hurricanes had higher past-month rates of illicit drug use, marijuana use, and cigarette use, as well as higher past-year rates of serious psychological distress, major depressive episodes, and unmet needs for mental health treatment or counseling in 2006 compared with those who were not displaced in the affected areas. Estimates for both analyses were based on the National Survey on Drug Use and Health (NSDUH) for 2006. The survey provided data on the prevalence, correlates, and patterns of substance use and abuse, as well as data on mental health problems and treatment. NSDUH is an annual survey of the civilian, noninstitutionalized U.S. population ages 12 or older, with interviews of approximately 67,500 people. 6 tables, 3 figures, and 22 notes