THREE in 10 British girls claim they have harmed themselves or know someone who has, some even before they reach their teenage years. Of the 1,000 girls aged 10 to 14 who took part in the survey, 9 per cent said they had harmed themselves while another 23 per cent had a friend or family member who had. The poll, by Mizz magazine, also found that the majority of girls (54 per cent) worry about being fat, while 17 per cent said they knew someone at school who suffered from an eating disorder.