A new study suggests that nearly one in five Gulf Coast residents experienced post-traumatic stress disorder in the aftermath of Hurricane Katrina.

The University of Mississippi findings, part of a research project funded by the National Science Foundation, were made public in August at the American Psychological Association’s annual conference in Boston.

Researchers said the level of post-traumatic stress disorder among the nearly 400 residents sampled after the 2005 hurricane appeared higher than among average citizens.

PTSD is defined as a strong emotional response with specific symptoms as a result of an event perceived as life threatening. Symptoms included flashbacks or dreams, avoidance of people or places associated with the event and increased arousal or trouble sleeping.

“In terms of PTSD prevalence, 19 percent responded in a manner suggesting a PTSD diagnosis as probable,” said lead researcher Michael Hirschel, a doctoral student in psychology. “This was a screening, not an in-depth interview process, so the total number of residents suffering from PTSD is unknown without additional follow-up.”

Conducted about five months after the storm blew ashore, the study surveyed 399 residents from Hancock and Harrison counties on the Mississippi Gulf Coast.

The study also examined a concept called general self-efficacy, which is a person’s belief in their ability to have an impact on their environment or on a desired outcome. Hirschel said the research indicated that an increase in general self-efficacy is associated with less psychological distress.

He said the primary aim of the research was to examine in greater depth the relationship between PTSD and general self-efficacy. The two have seldom been investigated in conjunction with one another in past research, and they have rarely been studied with samples of hurricane survivors, Hirschel said.