A show at a private girls' high school in Sherbooke, Que., went strangely awry when a young hypnotist left several students in "mass hypnosis" limbo and he had to call in his mentor to snap them out of it.

One student at Collège du Sacré-Coeur was reportedly left hypnotized for five hours until Maxime Nadeau, the young hypnotist, called his mentor to the school for an emergency intervention.

It all happened at an end-of-school year event last week, when Nadeau was hired to stage a hypnotism show for a small group of 12- and 13-year-old girls.

He worked on a small group while others watched the show. When it came time to end the event, several girls in the audience remained mesmerized and couldn't snap out of it, no matter what Nadeau did.

Nadeau didn't panic, because "it wasn't dangerous," he recalled in an interview with CBC's French-language service.

"Being in a trance is a state of well-being," Nadeau explained. "I wasn't stressed. I knew they would get out of it."

He called his mentor and trainer, Richard Whitbread, who made the hour-long trek to the school from his home in the town of Danville.

Whitbread found several girls were still under the effects of "mass hypnosis."

"There were a couple of students who had their heads lying on the table and there were [others] who, you could tell, were in trance," he said. "The eyes were open and there was nobody home."

Whitbread said he went through the process of making the girls think they were being re-hypnotized and then brought them out using a stern voice.

Whitbread said because his protégé is a young, attractive man, the girls could have been particularly influenced because they were keen to follow his directions.

Nadeau kept his cool dealing with worried teachers and parents, Whitbread said, but his overall inexperience may have played a role in the event's outcome.

Nadeau received about 14 hours of instruction prior to the show —. the basic amount of intensive training most people receive for basic hypnotism techniques.

'You're spaced out'

The girls later described being under the sustained spell as feeling spaced out, with heavy limbs.

One student who was watching the show said it felt like an out-of-body experience.

"I don't know how to explain it. It's like you're no longer there," Émilie Bertrand said. "You're spaced out."

Administrators at the school said they only learned after the fact that hypnosis isn't recommended for people under age 14, since young people are particularly sensitive to the experience.

School principal Daniel Leveillé said the staff didn't know the show could produce side-effects like those experienced by students in the audience.

Bertrand said even if the show effects lingered, everyone still enjoyed it.

"It was still a good activity," she said. "At the start, it was funny. Even if there were consequences after, I'd do it again."

Effects of hypnosis can linger

People who attend hypnotism shows can feel trance-like effects hours after an event, Whitbread said.

When it does occur, affected audience members usually approach the hypnotist afterward for assistance.