Updated

By Andrew Stern

CHICAGO (Reuters) - Golfer Tiger Woods' admission that he is undergoing therapy after having adulterous affairs has focused attention on the issue of sex addiction, a condition some experts say is becoming much more common.

But sex addiction is a controversial concept not currently recognized as an official diagnosis in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, considered the definitive word on psychological disorders.

"Certainly a lot of clinicians believe there is a clinical phenomenon of people who experience a lot of distress or get into a lot of trouble from having excessive sex," Zucker said.

"Anything in the sex and gender domain is controversial. Everyone has an opinion about sex. These issues raise the boundary between what's normal and what isn't -- and where do you draw the line," he said.

A number of clinics -- among them one in Mississippi where Woods has been reported to be receiving treatment -- have sprung up to treat sex addiction.

People undergoing this treatment have included celebrities such as actor David Duchovny. The U.S. cable TV channel VH1 recently ran a series "Sex Rehab With Dr. Drew" focusing on celebrities undergoing treatment for sex addiction.

Some psychologists opposed to conferring recognition on a diagnosis of "sexual addiction" describe it as a habit or a compulsion, akin to unrestrained gambling, and not an addiction that has a direct impact on brain chemistry.

"Sex addiction by itself is not a diagnosis we currently use," said Craig Fabrikant, a psychologist at Hackensack University Medical Center in New Jersey.

"It's like a lot of patterned behaviors that could be better described as obsessive-compulsive traits," he said. "Are people in a loving relationship oversexed? Is loving sex a sign of addiction? If it feels good, you do it."

"A chronic adulterer who gets caught might hide behind the term sexual addiction," Fabrikant said.

Nevertheless, treating someone who has numerous sex partners might be similar to treating a drug addict -- prescribing medication to calm anxiety and talk therapy to learn techniques to handle the urge, Fabrikant said.

'EMINENTLY TREATABLE'

Therapists who specialize in sex addiction say it is comparable to substance abuse and not merely a case of habitually accepting other people's offers of sex.

The stigma of sex addiction can keep people from getting help, but the problem is "eminently treatable," said Dr. Mark Schwartz of the Masters & Johnson Clinic in St. Louis, who treats patients for the condition.

Schwartz said he will often try to ease patients' anxiety with an anti-depressant medication, then talk to them about the roots of the behavior and help them understand the need for trusting, intimate relationships.

Woods made his first public appearance on Friday since revelations of repeated marital infidelity mired him in controversy in November. In his comments, the superstar golfer never explicitly identified the reason he was receiving therapy or detailed the type of treatment he was receiving.

"For 45 days from the end of December to early February, I was in inpatient therapy receiving guidance for the issues I'm facing. I have a long way to go. But I've taken my first steps in the right direction," Woods said.

He referred to "repeated irresponsible behavior," saying, "I was unfaithful. I had affairs. I cheated."

"The work that he's doing is probably going to fix it. That, along with the scrutiny from the press," Schwartz said of Woods. He said such problems can often wreck marriages.

The prevalence of online pornography and the Internet's ability to allow people to make connections to satisfy fetishes and find sex partners has helped foster what Schwartz described as an "epidemic" of sex addiction.

"When people who are genetically predisposed to addiction get hit by an addictive substance like cocaine or sex, it can grab them," Schwartz said.

"It's similar to drug and alcohol addiction in terms of the progression of it: sneaking around, having consequences, and engaging in the behavior despite the consequences," added Pittsburgh therapist Sandra Davis.

Frank Ryan, president of Addiction Professionals of New York, who works with substance abusers, said of Woods' behavior: "An addiction is an addiction. It's like an abscess, yet he continued to do it. He knew he would get caught. There's a piece of that that looks like insanity."

Davis said help was available from such groups as Sexaholics Anonymous and Sex and Love Addicts Anonymous, which borrow strategies from similarly named groups aimed at substance abusers who are intent on quitting.

(Editing by Will Dunham)