CASPER, CO - Thomas Willson used homemade needles, passed from prisoner to prisoner, to shoot up drugs at Arizona State Penitentiary. 

The drugs he could find were methamphetamine and heroin. And he could find them more readily in prison than on the street. 

Although meth put Willson in prison and ruined a promising swimming career, he considers himself fortunate. He has his teeth, and despite almost 20 years of intravenous drug use, he has tested negative for HIV and hepatitis C. 

"By the grace of a higher power, I didn't get anything," said Willson, 38. "I've probably collapsed a few veins, but I feel good. But I don't know what medical things might turn up in the future." 

Willson took a long time to stop blaming his past for his addiction and start looking for ways to heal - mentally and physically. 

He had his first puff of marijuana at 4 years old with his uncles and their friends. By 9, he was smoking regularly. 

Two separate stepfathers beat him. 

A doctor eventually noticed he'd had too many broken ribs, broken arms and other injuries for a boy so young. At 12, he was taken from his mother's home and went to live with his father in Kingman, Ariz. On the day California's Child Protective Services took him away, his face bore the bruised imprint of his stepdad's belt buckle. 

By 14, he was using methamphetamine. 

In high school, he was a promising athlete - a fact Willson thinks helped protect his health from years of drugs and neglect. 

He was a swimmer and says he even tried out for the 1984 Olympics in the breast stroke and butterfly. But he failed a drug test. Meth had come up as a "performance-enhancing drug," he said. 

Willson struggled with addiction for the next several years. 

He was sentenced to 7 1/2 years in prison at age 23. He had broken into a house and stolen a stereo for drug money. 

In prison, he complemented his meth addiction with a heroin one. Twice he got thrown into solitary confinement, where he was forced to quit cold turkey. 

He would shiver uncontrollably in the hole, then suffer unbearable heat flashes. His heart felt like it would explode. He dreamed monsters were coming after him to tear his head from his body. 

That was the first time he decided to give up drugs for good. 

Willson got out of prison in 2001. For a few months, he stayed clean. 

Then, a friend asked him to "baby-sit" another man who was trying to get off methamphetamine. Willson was a terrible choice. He and the man eventually went to find meth together. 

By then, Willson had turned into an ugly person. He carried a long knife, and often a gun. He started collecting drug money for a living. 

"I was allowing my addiction to take over. I was definitely capable of killing a man," he said. 

Drugs led him to Green River about five years ago. Soon after, he was jailed on an attempted first-degree murder charge. He had stabbed a man in the chest. 

Willson was facing 25 years in prison. Outside, his girlfriend was pregnant with his son. 

It was a low point and, Willson says, a turning point. Seeing mailed-in sonogram images of that tiny life convinced Willson that he wanted a better life for his child. 

He pleaded guilty to a reduced charge of aggravated assault after witnesses said the victim had attacked Willson first. He is still serving probation for that charge. 

He moved away from the drug users he knew in Green River and severed ties with many people from his past. He and his new family moved to Casper. 

Willson started working. He was learning what it meant to keep a steady paycheck and was on what he called the "marijuana maintenance program." He went to some of his treatment sessions stoned and submitted several hot drug tests to his probation officer. 

Finally, he decided it was time to quit for good. 

He wrote an autobiography, at the instruction of his doctor, and shared his innermost secrets with his therapy group. No one gasped in horror. No one judged him for his horrible actions. Many had similar experiences. 

Willson has been sober since Oct. 26, 2005. 

He marvels at the turn his life has taken. He says he has two of everything: two mortgages, two cars and two children. He is engaged to his girlfriend and is raising his son and his soon-to-be stepdaughter. 

He goes to Narcotics Anonymous meetings once a week. At each one, he hears something that keeps him going. 

He used to think, "To hell with God." What kind of God would put him through the life he lived? But someone once asked him, "What makes you think God didn't bring you through it?" 

Willson was one of the scheduled speakers last month at Casper's Fourth Annual Methamphetamine Conference, where he hoped that listeners would recognize themselves or people they love in his life, that it might prompt them to get the same help. 

Willson looks as lucky as he feels. 

He's up almost 80 pounds from when he was a slender addict who cared little for his next meal. He has a steady job at Eagle Uniforms. 

He says he is a good father - he reads to his children, plays pirate with his son and recently snapped dozens of photographs at his stepdaughter's school music program. 

He keeps a detailed weekly schedule. It helps him fill his time and ensures that he gets where he needs to be when he needs to be there. 

"I can only take it one day at a time. I know that I won't use today. That is what's important," he said.