Science & Tech

Percentage of Katrina survivors with mental disorders increasing

6 min read

New survey findings run counter to those from previous disasters

According to the most comprehensive survey yet conducted of people affected by Hurricane Katrina, the percentage of pre-hurricane residents of the affected areas in Alabama, Louisiana, and Mississippi who have mental disorders has increased significantly compared to the situation five to eight months after the hurricane.

These findings, which were presented last week to the U.S. Senate Committee
on Homeland Security and Government Affairs Ad Hoc Subcommittee on
Disaster Recovery
, counter the typical pattern found in previous disasters, in which the prevalence of mental disorders decreases with the passage of time.

“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,” says Ronald Kessler, Professor
of Health Care Policy at Harvard Medical School and director of the
study. “Our tracking surveys are designed to provide that information.”

The detailed findings of the new survey are in press in the journal Molecular Psychiatry.

The findings were developed from follow-up interviews with the Hurricane Community Advisory Group, a statistically representative sample of hurricane survivors assembled to provide information in a series of ongoing tracking surveys about the pace of recovery efforts and the mental health effects of these efforts on hurricane survivors.

In addition to Kessler, the study is led by researchers from Harvard Medical School and is funded by the National Institute of Mental Health, FEMA, and the Office of the Assistant Secretary of the Department of Health and Human Services for Planning and Evaluation.

Hurricane Katrina was the deadliest United States hurricane in seven decades, and the most expensive natural disaster in U.S. history. Over 500,000 people were evacuated, and nearly 90,000 square miles were declared a disaster area (roughly equal to the land mass of the United Kingdom).

Although Katrina struck more than two years ago, infrastructure reconstruction efforts continue to lag, raising concerns about long-term mental health effects.The Hurricane Katrina Community Advisory Group initiative was launched to provide an ongoing tracking survey of those effects. The data are designed to help support public health decisions.

The new data come from a follow-up survey from an original sample of 1,043 people who agreed to join the survey panel and to participate in repeated surveys over several years.

In the initial survey, published in August, 2006:

  • Seven percent of respondents reported experiencing an event that would be considered seriously traumatic (had to be rescued, any life-threatening experience, physical or sexual assault), and 18.7 percent reported that a traumatic event of this sort (including death) occurred to someone close to them.
  • The vast majority (84.6 percent) of respondents experienced a significant financial, income, or housing loss. More than one-third of respondents (36.3 percent) experienced extreme physical adversity and nearly one-fourth (22.8 percent) experienced extreme psychological adversity.
  • The estimated prevalence of anxiety-mood disorders in the baseline survey was roughly twice as high as found three years earlier using the same measures in a survey of residents subsequently affected by Hurricane Katrina.
  •  Socio-demographic variables were largely unrelated to these trends, suggesting that the short-term adverse mental health effects of Hurricane Katrina were equally distributed across broad segments of the population.
  • The prevalence of suicidality in the baseline survey was quite low, despite the high rates of anxiety and depression. This low prevalence of suicidality was traced to widespread feelings of optimism that the practical problems created by the hurricane would soon be resolved.
  • This optimism turned out to be unrealistic, raising the question of whether or not the slow pace of recovery increased the prevalence of suicidality. This possibility was investigated in the follow-up survey.

The typical finding in
post-disaster tracking surveys is that the prevalence of mental
disorders significantly decreases with time, with up to half of
post-disaster mental disorders typically resolving within a year and
the vast majority within two years.

But the new follow-up survey found quite a
different pattern after Hurricane Katrina:

  • The number of people with
    any anxiety or mood disorder did not change significantly between the
    baseline survey and the follow-up survey. (If anything, the trend was
    upward from 30.7% to 33.9%.)
  • The estimated prevalence of serious
    mental illness, in comparison, was significantly higher in the
    follow-up survey than the baseline survey in the total sample (14.0%
    vs. 10.9%) as well as in the sub-sample of respondents who are not from
    the New Orleans Metropolitan Area (13.2% vs. 9.4%). This trend was not
    significant, in comparison, in the New Orleans Metro sub-sample (16.9%
    vs. 16.5%).
  • The estimated prevalence of post-traumatic stress disorder (PTSD) roughly doubled in the
    follow-up survey compared to the baseline survey in the sub-sample
    exclusive of New Orleans Metro (20.0% vs. 11.8%), but did not change in
    the New Orleans Metro sub-sample (24.1% vs. 25.9%).
  • The prevalence of
    suicidality, finally, was significantly higher in the follow-up survey
    than the baseline survey both with regard to suicidal ideation (6.4%
    vs. 2.8%) and suicide plans (0.8% vs. 0.2%).
  • The suicidality trends,
    unlike those for anxiety-mood disorders and PTSD, were statistically
    significant and relatively comparable in magnitude in both the New
    Orleans Metro sub-sample and in the remainder of the sample.
  • The
    majority of respondents with baseline serious mental illness (SMI;
    51.1%) continued to have serious mental illness at follow-up, while
    30.8% improved (i.e., were classified as having less severe mental
    illness at follow-up) and only a relatively small minority (18.1%)
    recovered (i.e., no longer met criteria for an anxiety-mood
  • In the case of PTSD, 70.4% of baseline cases continued to
    have PTSD at follow-up, while an additional 10.3% were classified as
    having some other anxiety-mood disorder but not PTSD at follow-up, and
    only 19.3% recovered. Persistence was somewhat lower for suicidal
    ideation (37.9%), but much higher for plans (69.8%).
  • Improvement, in
    comparison, was comparatively high for suicidal ideation (49.9%), but
    not for suicide plans (16.0%). Recovery (i.e., no mental illness and no
    suicidality at follow-up), finally, was relatively uncommon for either
    suicidal ideation (12.2%) or plans (18.0%).
  • As noted above,
    researchers expected to find lower proportions of the population to
    have mental illness and suicidality this long after a disaster. Failing
    to find such a decrease, and instead discovering a number of increases,
    is an indication of the more severe adverse emotional effects of
    Hurricane Katrina than more typical disasters.

The researchers found that, as in the baseline
survey, socio-demographic variables were generally not significant
predictors of trends in anxiety-mood disorders or suicidality in the
two surveys, indicating that these adverse effects were widespread in
the population. The fact that hurricane-related stressors were still
quite common in the population nearly two years after the hurricane,
and that much of this could be attributed to these continuing stresses
suggests that efforts to address the problem of increased mental
illness and suicidality among Hurricane Katrina victims must confront
continuing needs for practical and logistical assistance, they said.

According to the researchers, providing the needed services to those affected may be
particularly challenging since many pre-hurricane residents of the
affected areas are now living elsewhere in the country. Still, they say, it is
especially important to reach these geographically displaced people
because of their comparatively high risk of serious mental illness.