Separating these two groups of people, he said, is the challenge when it comes to getting mental health services to those who need them the most. He said that one good approach would be to find the people who had experienced psychological consequences from Katrina and monitor them for psychological problems with this disaster.
Another challenge, he said, will be to make the best use of community resources. In short, he said, this is not a problem that psychiatrists can solve with antidepressants alone.
"This is not going to be just, 'What symptoms do you have?'" he said. "As an economic disaster, we will really need to focus on [residents'] purpose and identity."
If there is a silver lining, some psychological experts said, it is that the vast majority of those affected by the BP disaster have not suffered the loss of loved ones and other traumatic events.
"The present oil spill differs from the other disasters such as Katrina or 9/11 in that this tragic event occurred far away from the population centers and has not caused death and destruction of the magnitude we are familiar with in the case of other disasters," said Dr. Arshad Husain, director of the International Center for Psychosocial Trauma at the University of Missouri-Columbia School of Medicine. "However, the threat is slowly creeping towards the coast like a slowly spreading cancer."
Husain said the psychological effects of those who did not witness or lose loved ones in the explosion of the oil rig will be much different from those who have been more indirectly affected by the spill , such as those who have lost their jobs and way of life.
"This group has not lost any loved one or received personal injuries," he said. "Their dwellings and personal properties are not destroyed. Their recovery will depend on how well they are compensated for the loss of their income and how quickly they re-establish their businesses. ... This group, in my opinion, is at lower risk than the first group of having serious emotional reactions."
North said a major determinant of longer lasting mental health effects in the area will be how quickly the issues surrounding the spill can be solved.
"Of course, the best safeguard is to prevent damages to people's lives and the environment," North said. "Rapid and full restoration of the damages and financial restitution of losses is very helpful for emotional recovery. Perceptions of unfairness and perceived lack of concern for the welfare of those highly affected may be linked to negative emotional responses to the situation."
In the meantime, she said, offering a helping hand may help some cope.
"It should not be forgotten ... that people tend to be resilient by nature, and people helping one another in the face of hardship and tragedy can help reduce the emotional toll."