MIAMI (AFP) - Fallen Hollywood mogul Harvey Weinstein has reportedly checked in to a US rehabilitation centre that treats male sex addicts, but experts say such therapy is unlikely to help.

English comic actor Russell Brand, golfer Tiger Woods, rocker Ozzy Osbourne and actor Michael Douglas are among the high-powered celebrities who have proclaimed they were battling sex addiction - after their philandering was revealed.

While psychologists typically refrain from diagnosing someone from afar, some say Weinstein - who is accused of sexually assaulting a string of actresses over the years - fits the profile of a sexual predator, not an addict.

"I think you can control your impulses. He just decided not to do so," said Holly Richmond, a certified sex therapist in Los Angeles.

Therapists are also divided on whether sex addiction even exists.

The leading psychiatry reference, known as the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, updated in 2013, does not include sex addiction. Its authors decided it did not fit the definition of a psychological disorder.

According to Richmond, there is no such thing as a sex addict.

"What you should say is someone who has compulsive sexuality, or out of control sexual behaviour," she said.

"It is a behavioural issue. Sex is not the problem."

'Equine therapy'

The entertainment site TMZ has reported that Weinstein intended to fly to Switzerland for rehab, but decided to check in at The Meadows in Arizona instead.

The facility is home to what it calls the "nation's premier inpatient treatment for sex addiction", a 45-day programme titled The Gentle Path, that was attended by Tiger Woods after his cheating scandal.

It features group talk sessions, interactions with horses - coined "equine assisted psychotherapy" - yoga, art, meditation and one-on-one counselling.

A number of celebrities have sought treatment for drugs, alcohol and other problems at The Meadows, and many have been helped there.

But when it comes to treating sex addiction - and such programmes are offered at hundreds of clinics across the United States, costing between US$10,000 (S$13,499) and US$30,000 - some experts are dubious.

"There is no evidence that sex addiction treatment actually works," said David Ley, a psychologist in New Mexico and author of the book The Myth of Sex Addiction.

"After 40 years, there is not a single published study that shows that sex addiction treatment has a positive effect or actually help people change their sexual behaviour," he told AFP.

Ley says sex addiction is often just an excuse for avoiding personal responsibility.

"Sex addiction is a concept that has been used to explain selfish, powerful, wealthy men engaging in irresponsible sexual behaviour for a long time."

He pointed to a study done in Europe recently that looked at people in a sex addiction treatment programme and "showed that 90 per cent of them have another major mental health condition" and that sexual behaviours were merely symptoms.

Another aspect is cultural, part of living in a nation that elected Donald Trump president, even after he was heard on tape bragging about how he grabbed women by the genitals.

"These problems are occurring in a society that tolerates, allows and even may encourage powerful, wealthy men to do things that they can get away with," he said.

"Weinstein is engaged in these behaviours in a sexual way but I guarantee you that there are other aspects of his life where he is engaged in a deceptive, offensive, rude, domineering kind of behaviour," he added.

"Again, the sex is just the tip, of the iceberg."

Core issues

For counsellors who treat patients with sexual problems, Weinstein's pattern presents a deeper puzzle.

"Without seeing him I would never diagnose someone. But he definitely has traits of the compulsion, you know, sexually acting out," said Charlene Lewis, a certified sex addiction therapist in Miami.

"Part of addiction is denial. I think he is in a lot of denial about the damage he has done to these women." Four women have accused the 65-year-old producer of raping them, and more than two dozen actresses, including Angelina Jolie and Gwyneth Paltrow, say he sexually harassed them.

Lewis said any patient who wants to heal must really have the desire to change, recognise the harm their behaviour has caused, and be willing to probe the root of the problem.

"It goes back to what are the core issues? What are you medicating? What are you overcompensating for?

"Especially someone with that much power and that much prestige, what is really going on inside him?" She said successful sex therapy can take one to five years.

"There has to be a willingness to persevere through the process. It is not a quick fix."