WASHINGTON: The nightmare of 9/11 has indeed changed the way people dream, a new study says.

The terrorist attacks of September 11, 2001, which destroyed the twin towers of World Trade Centre in the New York city, has resulted in more intense dreams by people, sleep researchers at Tufts University and Newton-Wellesley Hospital in Boston said.

The researchers studied the dreams of 44 people, 11 men and 33 women living in the United States, between the ages of 22-70, who recorded their dreams for two years.

Each of the participants provided 20 consecutive dreams from their records, with the last 10 recorded before the tragic event and the first 10 after it.

The study, published in the journal Sleep, showed more intense images of dreams recorded after the attacks.

However, no dream involved images of airplanes or tall buildings or anything close to that, though all participants had seen the images of the incident many times on their TV sets.

Besides, the dreams were not longer and were more dream-like and bizarre.

''The more intense imagery is very consistent with findings in people who have experienced trauma of various kinds,'' said Ernest Hartmann, MD of Tufts University, who authored the study.

''The idea is that we all experienced at least some trauma on that day,'' Dr Hartmann said.