More Gulf Coast residents are thinking seriously about suicide or showing symptoms of post-traumatic stress disorder as the recovery from Hurricane Katrina inches on, a new survey finds.

The survey is a follow-up to one done six months after the hurricane, which found that few people in Louisiana, Mississippi and Alabama — about 3 percent — were thinking about suicide.

That figure has now doubled in the three-state area and is up to 8 percent in the New Orleans area, according to Ronald Kessler of Harvard Medical School, lead researcher for the Hurricane Katrina Community Advisory Group.

It may be six months before results are in publishable form, said Kessler, whose team interviewed 1,000 people last year and was able to track down 800 of them for this year’s interviews.

He said some preliminary results are striking. One is that about 21 percent of the 800 people interviewed showed symptoms of post-traumatic stress disorder, up from 16 percent a year earlier.

It’s not surprising, said Karen Binder-Brynes, a New York psychologist who specializes in PTSD. Katrina’s landfall on Aug. 29, 2005, was a one-time event, but its effects and their trauma remain strong, especially in New Orleans. In addition to losses due directly to the storm, violent crime, poor schools and other problems have piled trauma atop trauma.

Compounding the problem: local hospitals remain strained in their ability to deliver services. Also, community groups and police say the number of homeless people in New Orleans, many in need of mental health care, has almost doubled its pre-Katrina level and now stands at about 12,000.

“It’s a community that’s in terrible distress. It’s not like other things where, once everything’s over, everything’s getting rebuilt. On top of the original trauma there wre all these other traumas, and the sense of being sort of forgotten,” she said.

Kessler said that in the months after the hurricane, an underlying optimism protected many people from suicidal thoughts. That sort of “post-traumatic growth” is common among disaster victims.

Now, that optimism has worn thin, something the earlier report warned could happen if rebuilding didn’t keep pace with expectations.

Kessler, whose study is supported by the National Institutes of Health and the World Health Organization, said most disasters have relatively rapid recoveries, so rates for such ailments as depression and PTSD usually improve after a year.

The results of the New Orleans survey are more like those of people who lost their jobs in Detroit during the 1980s and couldn’t find new work than like those of most natural disasters, he said.

Binder-Brynes said that six months after Katrina, people were still concentrating on survival. “It isn’t until that’s more settled that the longterm mental symptoms appear,” she said.

The figures are likely to get worse, since the city has fewer psychiatric beds, psychiatrists and psychologists than before the storm, and many people have lost their jobs and no longer have insurance to pay for them, she said.

“It doesn’t just go away without treatment.”