London - Sex addiction really does exist, scientists say, and it may be driven by having too much of a "cuddle" hormone.
Despite claims that one in ten men and one in 12 women are sex addicts – including stars like Michael Douglas and Tiger Woods – many refuse to believe it is a real condition.
But now researchers say they have found differences in the genetic make-up of addicts.
They think this increases levels of oxytocin, the so-called cuddle hormone, which is said to make people bond and stay together.Those with excess oxytocin may be attracted to many people at the same time, leading them to compulsively seek out sex. The hormone is also thought to make sex more rewarding.
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Researchers, led by the Karolinska Institute in Sweden, looked at the blood of 60 people, mainly men, who were being treated for sex addiction.
They discovered important differences in their "microRNA" genetic material.
The study’s senior author, Professor Jussi Jokinen, said: "A lot of sufferers cannot control their behaviour and it can have adverse effects on their lives, from broken relationships to depression and anxiety.
"Based on our findings, and other researchers', there is em-erging evidence that sex addiction is a medical diagnosis which has a neurobiological cause."
Last year the World Health Organisation declared sex addiction a mental disorder for the first time.
The study, published in the journal Epigenetics, compared 60 sex addicts with 33 non-addicts, looking at ‘chemical tags’ on their genes. Researchers stressed the difference between people was very small, but enough to change their microRNA.
The findings could explain why cognitive behavioural therapy, which lowers oxytocin, helps addicts change their ways and could lead to a new drug to block the "cuddle" hormone.