By 12, girls have seen 77,500 ads. And does it make them happy?

By the time the average girl is 12 years old, her young, impressionable mind will have been exposed to more than 77,000 advertisements, according to an international study. Last week, it confirmed the link between the images of female perfection that dominate the media and increasing cases of low self-esteem among young women.

The research team surveyed 2,000 girls in the UK and the US aged between 10 and 14, with results revealing that 77 per cent of them reported feeling fat, ugly and depressed when faced with pictures of beautiful models and celebrities. More than half of these adolescents then described themselves in negative terms, using words such as "disgusting" and "ugly".

The study was undertaken as part of the stealth launch of a new Dove advertising campaign, which aims to highlight the pressures the beauty industry places on very young girls. The grainy viral film proved an instant hit on YouTube, receiving more than 380,000 hits in four days.

The film, Onslaught, opens with a shot of a smiling seven-year-old girl, then cuts abruptly to a barrage of images revealing every aspect of the beauty industry. Scantily clad models bear down from billboards; make-up adverts promote products promising to make viewers "younger, lighter, thinner, firmer"; and gruesome footage shows women altering their bodies through surgery. It ends saying: "Talk to your daughter, before the beauty industry does."

Dr Susie Orbach, a psychotherapist and author of Time to Talk, a book designed to help mothers engage with young daughters on body image and self-esteem, explains the possible effects of advertising on vulnerable individuals: "Young girls are bombarded by millions of images of digitally manipulated, airbrushed beauty every day, and research tells us this onslaught can often be responsible for feelings of low self-esteem."

As part of the study, girls were asked to keep a diary of the beauty images they were exposed to over three days, and to record their reactions. One 14-year-old girl wrote: "The images I see in magazines make me feel sad because I know I could never be that beautiful."

The effects of low self-esteem and bad body image are manifest in the high proportion of physical and mental health problems reported among the young women surveyed. Over 90 per cent complain of feeling "stressed and anxious" about their appearance on a daily basis, with 76 per cent turning to unhealthy activities such as eating disorders and self-harming as a way of coping with these emotions.

"Bad body image can lead to a depressive attitude and trigger very damaging behaviour," said Dr Phillip Hodson, a psychotherapist and author of Growing Pains, an advice book for troubled teens. "I don't think that we should go around blaming advertisers, but there is no doubt that they have a lot of responsibility to take the initiative for good or ill in terms of their effect on body image.

"Adverts like the new Dove one are a very good thing, but the bottom line is that they are still trying to sell you something to make you more beautiful."