Michael Fassbender plays the role of a man suffering from sex addiction in Steve McQueen's new film Shame

The new film Shame, starring Michael Fassbender as a sex addict, is rapidly acquiring critical acclaim, as well as prompting discussion about its controversial subject matter among the chattering classes.

Director Steve McQueen described sex addiction as an "extremely important issue" in a story "screaming to be told". The film sets out to raise the profile of a problem that is widely misunderstood.

Sex addiction, or hypersexuality, is a disorder that is often met by guffaws of scepticism and mockery, especially when A-list celebrities use it as an excuse for their infidelities.

It is soon to be formally recognised as a legitimate disorder, however, as research on the subject struggles to keep pace with the number of sufferers seeking help.

Psychotherapist for, Adrianna Irvine, who has worked with all kinds of addicts, said sex addiction can just as destructive as other forms of addictive behaviour and substance abuse.

"Sex addiction can easily destroy lives," she told International Business Times UK, describing the disorder as "a compulsion, not a rational decision", which impairs people's relationships, work and health.

Irvine referred to sex addiction as a "process addiction", mirroring conditions such as eating disorders. Sufferers see their sexual activity spiralling out of control and, due to a lack of understanding of the condition, many do not realise that they need help.

"First you meet a person who is sleeping with a lot of partners, then you uncover another layer and they are spending hours on internet pornography, then you find out about the escorts and the prostitutes and the total lack of control," she said.

She used the example of Tiger Woods, who many viewed as a possible sufferer of sex addiction when the scale of his infidelities - with up to 30 women - were laid bare in the media.

Rather than a pursuit of intimacy, Irvine said that sexual addiction is often a way of avoiding an emotional connection.

"I have a client who just made a breakthrough. They would always sleep with a man on the first date and through discussions they realised that they did this because they wanted to get the sex out of the way first," she said.

"It came down to anxiety over true intimacy. The sex itself became something used to create an emotional distance."

Addicts who have been caught being unfaithful may well promise their partners that they will never make the same mistake, but they are trapped in their condition if they are not aware of it.

"Sexual instincts come from the mid-brain, the animal part of the brain. That is instinctive - there is no choice on the matter. They have the same lack of control as an alcoholic trying to avoid a drink," she said.

When asked whether the increase in those suffering from sex addiction is a reflection of modern lifestyles, or if the condition is simply acquiring a larger profile, Irvine said she was unsure.

"It's a real question right now," she said. "It has certainly become less unacceptable as a condition. We certainly live in a culture where everything is at your fingertips. People have access to porn and the sex trade with the touch of a button, meaning they can quickly spiral into a compulsive problem.

"People seem more stressed as well. Our attention spans are shorter and we want things immediately. The quick fix of a sexual encounter is the same thing. People suffer with the guilt afterwards and the way for them to cope with it is simply to have another one."

As with any compulsion and addiction, Irvine said the key is to discover the triggers, whether they are problems in relationships, stress or intimacy, and find a way to control them. It is nearly impossible, and unwise, to attempt to go "cold turkey" with intimacy, she stressed.

"What we have sufferers do is actually work at re-setting their brain chemistry, changing the knee-jerk reactions and responses that will lead to them lapsing.

"It's a long road and is not easy, but sex addiction is a serious problem and one that a person has to confront to solve."

It is estimated that up to six percent or more of the population suffer from a form of sexual addiction, with up to one in five being women.