Sarah says she didn't want to die. Cutting gave her relief and helped her cope.

She was in a competitive private school environment and didn't fit in. Her parents were supportive and caring, but busy and she felt alone.

"It was a release,'' she says.

"And a bit of a cry for help.''

It took about six months for her parents to notice - Canberra's cold weather helped aid the deception. First she blamed the family cat but when that excuse wore thin she admitted she'd been self-harming and promised she'd stop. Instead she started cutting the soles of her feet, where no one would check.

Once her razor and scalpel were taken she catalogued the objects around her parents home into what could be used to cut and returned before anyone noticed. But looking at her, you would never guess - she is blonde, bubbly and confident but according to research from the University of Queensland Sarah fits the bill because there is no definitive profile or indicator for someone who will self-harm, other than age. Socioeconomic status, ethnicity or indigenous status play no role.

According to the same study over the course of their lives about a quarter of women and 18 per cent of men will self-harm at some point. For women, self-harming behaviour peaks in 15 to 24-year-olds; while men are most likely to harm themselves between the ages of 10 and 19. And in those high-risk years, the authors found, about 7 per cent of Australian youth aged 15-24 years engage in self-harm in any 12-month period.

It's a shocking statistic but doesn't surprise assistant professor in psychology at the University of Canberra Vivienne Lewis. Dr Lewis says although there are no definitive figures, she and her colleagues believe cutting behaviour is on the rise and dramatically under-reported.

A spokeswoman from ACT Health said the directorate did not collect statistics on ''cutting'' or presentation to hospital with deliberate self-harming behaviour. But the most recent Australian school study found only 10 per cent of young people who self-harmed would seek hospital treatment.

''More adolescents are coming forward with self-harming and certainly we seeing more presentations as psychologists - it's not uncommon to see adolescents who are presenting with depression, anxiety and self-harm as part of that,'' Dr Lewis says.

She said some teens were influenced by friends.

''They see their friends who are self-harming and they copy it,'' she said. ''It's to try and reduce stress or an outlet for anxiety, that's one reason.''

She said the internet also had a great deal of information about different forms of self-harming behaviour that teens accessed.

''That might be one of the reasons why it's increasing now compared to 10 years ago as kids had less access to finding out ways of self-harm,'' she said. ''Self-harm is an expression of distress and we are seeing adolescents that are more stressed.''

Dr Lewis says self-harming and cutting behaviour was often dismissed as ''attention seeking''.

''It's a way of trying to display I'm not coping, I'm feeling distress. Parents should get help as soon as they discover it, often by the time parents discover it, it has been going on for a while, parents usually notice it by accident.

''A lot of the adolescents I talk to say that when they cut they feel a bit of a relief - it's like a distraction technique in some ways from whatever psychological pain is happening.''

Manager of headspace ACT Nic Hubbard said the Canberra branch did not have complete figure on self-harm but it was on the rise.

"A large proportion of young people who use our service engage in self-harming behaviour.'' She said teens at risk often had a history of depression, were socially isolated or living alone or suffer bereavement in childhood.

Sarah hasn't cut herself for more than three years.

"Sometimes I feel like it but I have other things I can do, sometimes I go out with friends and get drunk, or I can go to the gym. I feel like it's under control,'' she says.

"I'm happier.''

At school she wasn't the only girl cutting. Her friends knew about it and it wasn't a big deal.

No one really got involved. But it impacted her whole family.

''My mother said it broke her heart - if she catches sight of the scars she still finds it hard.''

Explaining the pattern of scars down her thighs can be awkward with a new partner but she says most of her peer groups know someone who has done the same thing so it's not really a shock.

■ *Not her real name. Sarah agreed to talk on the condition of anonymity. Lifeline offers free telephone crisis counselling service on 131 114.