North Dakota health officials are warning parents and educators about the so-called "choking game," in which a person cuts off oxygen to the brain for a quick high without using drugs.

Health officials say at least one youngster has died in North Dakota as a result of it, though other accidental strangulation deaths may have been ruled suicides.

Health Department spokeswoman Dorcas Kunkel said the game has been around for decades - also known by the names "flatliner," "blackout," "ghost" "pass out" and the "dream game" - and goes on out of sight of most adults.

"The kids who participate in this behavior are generally ages 9 to 14," Kunkel said. "To many children, the choking game seems like a harmless way to get a rush. Unfortunately, it can be deadly."

Children do it alone or at parties, officials said. Belts, neckties, dog leashes, bed sheets and shoestrings are often used.

Dr. Craig Lambrecht, the state medical officer, said he has treated several children with injuries from the activity over the years.

"As parents, we sometimes think that things like this don't happen in North Dakota. But I can emphatically say they do," Lambrecht said.

The deaths often are listed as suicides, accidental hangings or asphyxia due to hanging, making it difficult to get an accurate count, health officials say.

Loreeta Canton, a state Health Department spokeswoman, said officials researched children's death certificates over the past several years, attempting to find out how many deaths in the state could be attributed to the choking game. They found only one case that could be directly attributed, she said.