Elizabeth Smart has appeared in an anti-porn video and said that X-rated films made Brian David Mitchell, who kept her prisoner as a sex slave when she was just 14-years-old, worse.Now 28, Smart was taken from her bedroom in Utah during 2002 when she was only 14 years old.

Smart, now 28, was snatched from her bedroom in Utah during 2002 when she was only 14 years old. She was held for nine months by Brian David Mitchell and Wanda Ileen Barzee, at Mitchell's home.

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Mitchell, 57, raped Smart repeatedly, often several times a day, forced her to drink alcohol, smoke marijuana and forced her to view porn films with him.

In the hard-hitting video, Smart believes that watching sexually explicit films were the reason she was kidnapped by Mitchell.

The film was released by Fight the New Drug, a non-profit organisation that aims to "provide individuals the opportunity to make an informed decision regarding pornography," according to its mission statement.

"All I know is that pornography made my living hell worse," she says in the film.

"It just led to him raping me more, more than he already did, which was a lot.

"Looking at pornography wasn't enough for him. Having sex with his wife after looking at pornography, it wasn't enough for him.

"And then it led him to finally going out and kidnapping me.

"He just always wanted more. I can't say that he would not have gone out and kidnapped me had he not looked at pornography."

After she was rescued by police officers, Smart has become an outspoken campaigner against sexual abuse and pornography. She is now head of the Elizabeth Smart Foundation, which helps prevent crimes against children and educates kids about how to protect themselves if they're mistreated by a stranger.

In 2011, Mitchell was sentenced to two life terms in the high-security unit at the US Penitentiary in Tucson, Arizona. His wife, Wanda Barzee, received two terms of up to 15 years in prison, including seven that she had already served.

A US study in the Behavioural Sciences Journal claims that watching porn causes changes in the brains of people suspected of having compulsive sexual behaviour (CSM) disorders that resemble those in drug addicts when they take narcotics.

Some sex therapists claim they have treated children as young as 10 for 'pornography addiction'.

However, the current Diagnostic and Statistical Manual of Mental Disorders, DSM-5, which classifies mental disorders, does not include CSM, pornography addiction or sex addiction as identifiable mental illnesses.

The American Psychological Association (APA), which oversaw the creation of DSM-5, says there have been too few studies into whether the conditions exist and can be diagnosed for them to be included.