A new study of Russian roulette is shedding some light on the psychological similarities and differences between taking great risks and committing suicide.

Scientists at the University of Miami School of Medicine examined the case records of 20 Russian roulette victims -- 19 men and one woman -- recorded in the Dade County, Fla., medical examiner's office from 1957 to 1985. During the same period, there were 6,534 suicides, of which 95 were used as a control group.

The researchers concluded that "being young is an important predisposition to playing Russian roulette," and so is being depressed.

Of those who died playing roulette, the mean age was 27.7, compared with a mean age of 50 for those who intentionally shot themselves in the head to commit suicide, the researchers reported in the May issue of the American Journal of Psychiatry. Half of the roulette victims were depressed.

"Roulette was once considered a form of suicide," said Dr. David A. Fishbain, the study's main author. "The issue is whether they are true suicides or not. We were unable to make the conclusion either way."

The earliest descriptions of Russian roulette come from "A Hero of Our Time," a Russian novel published in 1840. The game itself is characterized by the researchers as "the ultimate game of chance, the gamble with death, the testing of fate, the identification of it as an act of bravado and the demonstration of an extreme form of risk-taking behavior."

In Russian roulette, a single bullet is put into one of six chambers in a revolver. The cylinder is spun and the gun placed at the head, and the trigger is pulled. If the gun does not fire, the bullet is passed to the next player.

In one of the first studies of its kind, they found the following characteristics for those killed in Russian roulette:

Just over half were single, compared with only 13 percent of the suicide victims. Roulette victims were far more likely to live with someone and be a student.

Nearly 95 percent of the roulette victims were in good or very good health, compared with fewer than half of the suicide victims. All of the roulette victims died with others around them, while more than half of the genuine suicides died alone.

Drugs, alcohol and a history of psychiatric disturbances were associated with nearly 60 percent of the deaths caused by Russian roulette but only about quarter of those who committed suicide.

Half of the roulette victims were depressed, Fishbain said, but not as depressed as the suicide victims (nearly 80 percent were depressed). Because risk taking is thrilling, even if the consequence is death, it may be the rush of the risk that temporarily relieves their depression.

"They use risk-taking behavior as a form of self-treatment for depression," Fishbain said. "They use risk taking as a way of controlling their depression."

As evidence of the roulette players' willingness to take risks, the researchers pointed out that more than half had fired the gun more than once. More than a quarter had played the game before, and 16 percent (three of the 19 men) had placed more than one bullet in the gun.