Dark water: Hurricane Katrina is likely to cause long-term mental health problems. Credit: Reuters/Lee Celano

When Michael Charness arrived at a makeshift Texas hospital in October, ready to treat those who had fled their homes after Hurricanes Katrina and Rita, he was quickly overwhelmed by the number of people with behavioral issues. “Soon after we began to work with them, we began to see the magnitude and volume of mental health problems,” says Charness, chief of staff for the Veterans Administration Boston Healthcare System.

Solid numbers are unlikely to be available for months, or even years, but according to informal surveys of people in the facility, about half have mental health problems, and nearly one-third show signs of post-traumatic stress disorder (PTSD). “Even if only a small percentage of hurricane victims go on to develop new mental health problems, the number could be staggering because of the large scale of the disaster,” says Farris Tuma, head of disaster research at the US National Institute of Mental Health (NIMH).

Effects are more likely to linger when severe trauma is coupled with community destruction. Fran Norris, Dartmouth Medical School

In the aftermath of disasters, many people experience intrusive thoughts and insomnia, but few suffer long-term consequences. Unfortunately, Katrina featured many of the ingredients that trigger persistent disorders. “Effects are more likely to linger when severe trauma is coupled with community destruction,” says Fran Norris, a psychologist at Dartmouth Medical School.

Based on data from 132 different disasters over the past 24 years, Norris has found that risk factors for PTSD include injuries, life-threatening situations, bereavement, displacement and financial loss. Minorities and people from lower socioeconomic class are also at greater risk.

Researchers plan to study efforts to get 'psychological first aid' to thousands of victims, many of whom will recover on their own, as well as programs for people who develop psychiatric problems, such as depression and PTSD. The NIMH will support some of these efforts with RAPID research grants.

A primary challenge will be to find the small proportion of people most likely to suffer long-term problems. “We'd like to be able to identify people at risk with gene expression or biomarkers, like you do for people who are at risk for a stroke,” says NIMH director Thomas Insel.

No such clinical tests are available as yet, but scientists have found some promising candidates. Researchers at the Hadassah University Hospital in Jerusalem measured gene expression of a subgroup of blood cells in emergency room patients who came to the hospital after trauma, such as terrorist attacks. They found that gene expression signatures recorded during the emergency visit and four months after predicted which individuals met diagnostic criteria for PTSD (Mol. Psychiatry 10, 5; 2005). The results could aid early detection and intervention efforts, they say.

However, further research on these types of biomarkers is unlikely to take place with victims of Katrina, because of ethical concerns associated with asking people for blood samples so soon after a horrific event, says Insel.

In the meantime, Ron Kessler, a healthcare researcher at Harvard Medical School, plans to follow 1,000 people displaced by the hurricane for at least two years to track the ongoing stresses and psychological effects, as well as their access to medical care.

Surveys such as these will also help determine how treatment patterns have changed since 9/11 and other disasters.