Dr Gomathi Sitharthan of the Faculty of Health Sciences and Professor Raj Sitharthan from the Department of Psychiatry of the University of Sydney conducted an online study of 800 people who watch porn to gain an unprecedented insight into who suffers from porn addiction and how their addiction affects them.

Preliminary results from the study have revealed that 43 percent of those surveyed started to view porn between the ages of 11 and 13, 47 percent spend between 30 minutes and three hours a day watching porn. More than half of porn users surveyed were married or in de-facto relationships and 85 percent were male.

The researchers found excessive users had severe social and relationship problems and had often lost their jobs or been in trouble with the law as a result of their addiction. Some users escalated their viewing to more extreme and often illegal material.

"We all know what porn is, but until now we haven't known much about its impact," says Dr Gomathi Sitharthan.

"Gone are the days when you had to go to a shop, pay for the merchandise, and come out with a magazine in a brown paper bag."