Washington, Feb 3 : The stress brought on by the terrorist attacks on the twin towers of World Trade Centre on September 11, 2001 has changed the way people dream, according to a new study.

Dr. Ernest Hartmann of Tufts University and Newton Newton-Wellesley Hospital in Boston, Massachusetts followed 11 men and 33 women living in the United States, all between the ages of 22-70 years, who had been recording all their dreams for at least two years.

Each volunteer provided 20 consecutive dreams from their records, with the last 10 recorded before 9/11/01 and the first 10 after 9/11/01.

Dr. Hartmann said that dreams after 9/11 appeared to show more intense images, but were not longer, more dreamlike or more bizarre.

Additionally, the dreams did not contain images of airplanes or tall buildings. In fact, not a single dream involved planes flying into towers, or anything close to that, even though all participants had seen those images many times on TV.

"The more intense imagery is very consistent with findings in people who have experienced trauma of various kinds. The idea is that we all experienced at least some trauma on 9/11/01," Hartmann said.

The research team suggested that adults take between seven to eight hours of nightly sleep.

The study is published in the journal SLEEP.

ANI