Bogota: A total of 42 Colombian students taking part in a hypnotism show at a school in the southwestern city of Mocoa were unable to come out of a trance and suffered an attack of mass hysteria, school officials said.

The principal of the Mocoa City Educational Institution, Daniel Mora, said that "30 or 40 minutes after the end of the show, which also included clowns and jugglers, the students were back in their classrooms, when suddenly they all started yelling at the same time".

The institution's psychologist was immediately called and public health authorities sent some 10 psychologists and psychiatrists.

In a preliminary diagnosis, the psychologists decided that what they were seeing was a mass-hysteria syndrome, so the students were taken to the nearby Jose Maria Hernandez Hospital.

There 'they were given first aid, hydration and epilepsy control', hospital deputy director Monica Guerrero informed, adding that it was unnecessary to prescribe any medical treatment for them.

"Of the 42 children, 36 of those attended were either unconscious, showed signs of nervousness or, in two cases, had symptoms of epilepsy," Guerrero said.

She also said that once they were admitted they were put under the care of the hospital's psychology department, which diagnosed 'collective neurosis induced by the hypnosis event'.

All those affected were gradually released on the same day, while the magician, Miller Zambrano Posada, was taken into custody pending possible charges.