U.S. Rep. John Sullivan, who is returning to Washington after a 30-day stay in a treatment center for alcohol addiction, said Monday he plans to work harder than ever and will seek re-election next year.

The four-term Republican checked into the Betty Ford Center in California on May 28. In a phone interview with The Associated Press, Sullivan said no single incident led him to seek help for his alcoholism, a decision he made as his drinking began to escalate and cause problems in his family.

"The last couple of months, I was drinking more, mainly at home on weekends in front of my kids and my wife," said Sullivan, 44, who lives in Tulsa with his wife and four young children. "There wasn't anything like a DWI or something crazy that happened. It was just a personal choice — I wanted to eliminate alcohol in my life."

Sullivan planned to attend a fundraiser in Tulsa on Monday night and return to his Washington office on Tuesday.

He said his drinking did not interfere with his job as congressman and that his professional success actually prevented him from seeking help.

"I've done my job very well, and that's one of the ways I fooled myself into thinking I didn't have a problem," he said. "I never was drunk on the House floor and I never was drunk at work.

"But I needed to get help to stop. I tried quitting on my own ... but I failed every time."

Sullivan said he has emerged from treatment as a stronger man with a new outlook on life.

"It turned out to be a wonderful experience," he said. "Even though it was embarrassing having it out there publicly, I don't have to keep it a secret anymore."

That a high-profile, successful politician acknowledges publicly he is an alcoholic can send a positive message to other functioning alcoholics, said Donna Woods Bauer, director of the Oklahoma Citizen Advocates for Recovery and Treatment Association.

"This isn't a case of a bad person getting good. It's about a sick person getting well," Woods Bauer said. "It's about recovery as a reality in Oklahoma. He's saying: `I needed help. I got it. And recovery does happen.'"

A former member of the Oklahoma House, Sullivan first was elected to Congress in 2002 in a special election to replace Steve Largent, who made an unsuccessful run for governor.

In 2008, Sullivan defeated Democratic challenger Georgianna Oliver with 66 percent of the vote, his widest margin of victory.