One-quarter of those who lived in Louisiana and Mississippi experienced extreme psychological adversity during and after Hurricane Katrina, a survey finds.

The survey also found that one-third experienced extreme physical adversity and the vast majority of people affected by Hurricane Katrina experienced a significant loss in finances, income or housing.

Nonetheless, there is also evidence of an enormous amount of strength and personal growth in the sample, with 88 percent of the survey respondents saying that their experiences with the hurricane helped them develop a deeper sense of meaning or purpose in life, according to study leader Ronald Kessler of Harvard Medical School.

“It is important for mental health policy planners to have accurate information about the size of the problem they are trying to address among survivors of Hurricane Katrina. Our tracking surveys are designed to provide that information,” said Kessler.

More than 1,043 people agreed to participate in repeated surveys over several years to track the pace of recovery efforts and the mental-health effects of hurricane survivors.

One-fourth of survey respondents reported having nightmares about their experiences in the hurricane in the past month, while almost 80 percent of those from New Orleans reported being more irritable or angry.