A recent survey conducted by a research team in the University’s psychology department shows 8 percent of 188 students met the criteria for a diagnosis of post-traumatic stress disorder after the Sept. 11 attacks.

The survey was given to undergraduate psychology students for extra credit. Patricia Frazier, a psychology professor, conducted the study and said the terrorist attacks offered a unique opportunity to document tragic events’ positive and negative effects.

“Sept. 11 was an unprecedented event where no one was in control,” Frazier said. “I was interested in how this loss of control would affect people.”

Although many students felt some loss of control after the attacks, Frazier said the team was surprised to find many individuals felt they had some control over the situation through their belief in a god.

Those who believe in a higher power showed fewer signs of post-traumatic stress disorder than those who believe the events were controlled by individuals, according to the study.

Individuals who believed a god was in control reported more positive life changes, while those who did not reported fewer positive changes.

Those changes included a better appreciation of life, closeness to family and beliefs in the goodness of people.

Half the students surveyed thought the biggest effect was positive, while 45 percent said it was negative. Five percent had mixed feelings.

Many students reported feeling negative change in their lives in areas of safety, fairness and justice.

Ninety percent reported experiencing at least one symptom of post-traumatic stress disorder, the study says. A similar November study conducted by the New England Journal of Medicine found the same result.

Because of the small sample, it is unclear if the results could be representative of the University as a whole, Frazier said. She added she did not know whether the fact only psychology students were surveyed would affect the results.

“Although clearly not a random sample of the population, given the uniqueness and tragedy of the events it is important to assess their effects on a broad range of people within the U.S.,” the team wrote in a summary of the study.

The research group hopes the survey will help reveal more about this kind of trauma in case an event like Sept. 11 should occur again.