Researchers found that a year after Hurricane Katrina pounded the Gulf Coast, survivors have experienced a doubling rate of serious mental illness in the months following the natural disaster. The Harvard study also found, however, that thoughts of suicide have diminished from levels documented before the storm. The researchers attributed the finding to an increased level of optimism and resiliency among the survivors.

As the largest study to date on this issue, the researchers relied on a list of 1.4 million families provided by the American Red Cross (ARC). The survey, conducted between January 19, 2006, and March 31, 2006, included interviews with 1043 adults from the ARC list who resided in areas affected by the hurricane. The responses were compared with the results of an earlier survey conducted in 2001 and 2003, which involved 826 adults in the same census areas of Alabama, Louisiana, and Mississippi.

The study, reported in a special on-line edition of the Bulletin of the World Health Organization (August 28, 2006), indicated that post-Katrina participants were about 2 times as likely to have serious mental illness (11.3% vs 6.1%) and mild-to-moderate mental illness (19.9% vs 9.7%). Of the group with serious mental health problems, an estimated one third to one half experienced posttraumatic stress disorder. The researchers are now conducting a 6-month follow-up phase and plan to conduct 12-month and 18-month follow-ups as well.