Controversy surrounds the concept of sex addiction, but 3-5 per cent of the population fit the criteria, writes Eoin Burke-Kennedy
Asked to define a nymphomaniac, the sexologist Alfred Kinsey sarcastically replied it is simply "someone who has more sex than you." Kinsey's reply captures a standard response to sex addiction, namely that it is some kind of bogus modern malaise conveniently deployed by people who cheat on their partners or by celebrities caught in flagrante delicto.
The term sex addict came into vogue in the 1980s, when US psychologists suggested certain individuals were addicted to the neuro-chemical changes that occur in the body during sexual behaviour, much the same as a drug addict gets hooked on heroin.
Although there has never been any strong scientific evidence to support this claim, the theory suggests addicts are not having sex for reasons of physical pleasure but as a comfort from pain, stress or feelings of inferiority.
Most psychiatric associations do not currently recognise sex addiction as an illness and therefore there are no official diagnostic criteria, but therapists talk of compulsive masturbation, frequent sex with prostitutes or with multiple partners, or repeated patterns of sexual behaviour with increasingly negative consequences for the individual or others.
Some psychiatrists, however, suggest the term sex addict is an over-simplification which may mask other underlying psychological causes of increased libido and problematic sexual behaviour. Sceptics also contend that libido varies greatly from person to person, and an unusually strong sex drive should not be confused with dysfunction.
They also argue that normal sexual behaviour can be compulsive and not all compulsive behaviour is addictive.
But Eoin Stephens, director of training at the Irish Centre of Sexual Addiction, says there is a difference between the everyday use of the word "compulsive" and the clinical use of the word.
"Someone who has a strong passion or appetite for sex is not the same as someone who feels compelled to do something despite the negative consequences."
The typical profile of an sex addict, he says, is someone who is a bit uncomfortable in close relationships or who may feel vulnerable and isolated.
"When they come across something like telephone sex, internet pornography or prostitution, they find it a more exciting and safer way to get sexual gratification," says Stephens.
"It's not real life sexual relations that people get addicted to, because they are too complex," he says.
Based on the number of individuals seeking treatment, about 3-5 per cent of the population meet the criteria for sexual addiction and compulsivity, according to US-based Society for the Advancement of Sexual Health.
But the organisation says this may be a conservative estimate because - as is the case with most addictions - the majority of people suffer with the problem rather than seeking treatment.
Consultant psychiatrist Brian Sweeney says addictions can be seen as subversions of the natural reward pathways in the brain. The neurotransmitter dopamine appears to be one of the key neurological pathways by which ordinary human behaviour is controlled, says Sweeney.
"So the brain chemically rewards behaviour connected to its evolutionary survival like eating and sex.
"Addicts - through say drugs or pornography - are short-cutting these reward pathways and that is what makes them so destructively addictive."
The internet has been described by some addicts as the "crack-cocaine of sex addiction", permitting instant, anonymous access to all kinds of pornography at the click of a button.
Clinical director of Lifeworks addiction treatment centre in the UK, Liz Cervio says the internet has created a new type of sex addiction, known as hypersexuality, where addicts become dependent on cybersex which is completely removed from real world relationships.
"You used to have to leave the house to access these things, but the internet makes access to high risk material for people with sex addiction much easier and more secretive.
"Sex addicts struggle with what we call the three Cs - loss of control, compulsion to use and continued use despite negative consequences."
Recovery from sex addiction can be more complex than other addictions because of the difficulty in defining sobriety.
Abstaining from sex altogether is not a realistic or healthy option from most people.
"With heroin or alcohol, you can clearly define what needs to be avoided. It is a little less clear for a sex addict where the line between healthy and unhealthy gets drawn, and it may not be in the same place in early recovery as in later recovery," says Stephens.
"Often early on, people may have to avoid most forms of sexuality but the hope is that as recovery progresses they develop a healthy sex life."