Research suggests an estimated 2 percent of people, or about 3 million nationwide, purposefully hurt themselves, said Cheryl Cozzens, a licensed clinical social worker at Utah Valley Regional Medical Center. The behavior often starts in the teenage years but may persist much longer.

The rate increases dramatically for teenage girls, jumping to about 10 percent of that age group, she said, adding her practice reflects that number. Cutting is so common among young women with eating disorders that it's sometimes called "new-age anorexia."

Though females appear to cut more than males, there is growing evidence that men and boys do it more than once believed.

Cozzens has also noticed a disturbing trend.

"I'm seeing younger and younger patients that are engaging in it. . . . I hate to use the word cult. It is taught and passed on in their peer groups." Her youngest client is 12.

Cutting is complex behavior and not well understood, even among mental health professionals. Sometimes it is mistaken for a suicide attempt.

"It's still kind of a mysterious thing," said Ruta Mazelis, who publishes "The Cutting Edge: A Newsletter for People Living with Self-Inflicted Violence," based in Ohio. "The secrecy surrounding the behavior remains quite intense."

Cutters typically have deep-seated emotional problems. Many are the victims of childhood sexual or physical abuse. Cozzens says about 80 percent of her patients were abused.

Abuse victims might see themselves in competition with their tormentors, said Rob Pramann, clinical director at Shepherd's Staff Christian Counseling Center in Sandy.

"They inflict the injury on themselves to show they are in control of the pain. It's a kind of re-enactment of the abuse."

Self-injurers also may suffer from a number of mental illnesses, including major depression, borderline personality disorder or post-traumatic stress disorder. They have extreme mood swings and trouble maintaining relationships.

"A lot of it is just a self-hatred thing," Howell said.

Howell, a college student studying electronics, figures he has sliced himself no less than 500 times, mostly with a blade extracted from a disposable razor. He bears the scars of a chronic cutter. His upper arms, especially the left one because he is right-handed, look like well-worn cutting boards. The last time he cut was seven or eight months ago, about the time he was diagnosed with borderline personality disorder.

He did most of his cutting during his high school years when he was particularly depressed.

He had few friends. He wanted a girlfriend but couldn't get one. He was devastated when a girl he'd dated a few times dumped him.