Most football fans have heard of Herschel Walker.

Many of these same people know Walker won the 1982 Heisman Trophy during his junior year at the University of Georgia and he was a top running back in the NFL.

Fewer of these folks can rattle off his professional football statistics, which include the title as the only player to to tally more than 10,000 yards from scrimmage and 5,000-plus return yards.

However, for years only a handfull of people knew that Walker had a dark side.

On a recent afternoon, Walker gave a speech at Madigan Army Medical Center, during which he talked about his life coping with mental illness.

Just shy of a decade ago, Walker was diagnosed with Dissociative Identity Disorder, a mental illness formerly known as multiple personality disorder, a condition that is characterized by symptoms ranging from amnesia to alternate identities, which usually develops as a reaction to trauma.

The symptoms of the disorder probably began for Walker at about age 6, he said.  He was an overweight child with a speech impediment who was bullied at school, he said. 

"Kids made fun of me because I was fat and had a stutter," he said. "I created alter (personalities) to handle their abuse."

For the first decade or so of his life he had no interest in sports, instead spending his time reading and writing poetry, he said. Then at age 12, he spent the first of many years pushing his body to the limit with 100,000 push-ups, 100,000 sit-ups and sprinting thousands of miles, he said.

In high school he was valedictorian of his class, he played football, basketball and competed in track and field. He racked up many milestones, including scoring 85 touchdowns as a running back in leading his team to a state championship. One year after he joined the pros, he earned a bachelor's degree in criminal justice from the University of Georgia.

Walker's condition went undiagnosed for years, he said.  He became concerned when his ex-wife kept telling him about things that he had done that he did not remember, he said.

"I threatened to kill a man because he brought my car to me late," said Walker, who was born in Augusta, Ga. "I won a Heisman Trophy but I don't remember it.  I put a knife to my wife's throat but I don't remember it.  I played Russian roulette. I would take a gun and put it in my mouth and pull the trigger, but I don't remember it."

Although Walker excelled in everything he did, he suffered, he said. He started getting treatment when he realized that his life was out of control, the former running back said.

"I had one guy who went to college, one guy who played for the Cowboys, Eagles and Giants ... one guy who wanted to kill himself...one guy wanted to kill someone else ... and one guy who would have killed his wife if he had not gotten help," Walker said of his alternative personalities.

Later, as part of his therapy, in 2008 he wrote a 256-page memoir called "Breaking Free: My Life with Dissociative Identity Disorder. " In the book, Walker revealed that he had suffered from DID for years.

After nearly a decade of treatment, he has never taken medication.  He chooses instead to write in a journal and travel around the country speaking about the disorder to raise awareness and encourage others who suffer from the condition to seek help.

"DID is not ‘Sybil' or ‘Three Faces of Eve.' DID is just an illness that people are dealing with," Walker said.

For more information about Walker and his book visit the Web site at www.herschelwalker.net.