Eating disorder sufferer Rebekah Dowell: "I felt... like no-one wanted to help me"
Doctors are calling for an urgent review of adolescent healthcare because they say too many young people are getting lost in the system.
They say there are problems treating 16 to 18-year-olds with both mental and physical illnesses.
The Royal College of GPs wants more targeted provision for teenagers.
Care services minister Phil Hope said: "Mental health services have improved a lot in recent years, but we know we need to do more."
Experts say healthcare for teenagers is patchy and often there is an additional problem with the transition between child, adolescent and adult services.
I felt like no-one wanted to help me, and I lost a lot of weight
Professor Steve Field, chairman of the Royal College of GPs, said: "The handover between child and adult services is not done very well in most places."
Getting healthcare can also be difficult because symptoms are often hidden even from close family members and advice from doctors is often ignored.
Some of the areas highlighted by GPs involve the treatment of conditions like diabetes and asthma. But this age group is particularly vulnerable to mental health problems such as anorexia.
Many of those suffering from eating disorders say they still have to wait months for treatment and when it comes it is inappropriate. Sometimes under-18s are still treated on adult psychiatric wards.
Hannah Bliverstone, 17, from Hertfordshire, is critical of the treatment she received for an eating disorder.
The teenager said she did get the care she needed after becoming desperately ill. However she became so weak that she could not walk and instead had to shuffle along the ground.
It was a year before Hannah got any specialist help for her eating disorder. Even then she had to move between three different hospitals.
She said: "At my most needy I was not given the correct treatment. My life became a living hell. I lost two years of my life. I was consumed by my illness. I don't want others to suffer in the same way."
Meanwhile Rebekah Dowell, from Liverpool, said that in the crucial month when she needed urgent treatment for anorexia, different authorities argued about whose responsibility she was.
She said: "I wanted to go into hospital and I wanted the treatment. But I was getting stressed about it. I felt like no-one wanted to help me and I lost a lot of weight."
It is hard to generalise about the correct way to treat serious teenage health problems. What is appropriate will depend on the individual and the specifics of every case.
Some doctors argue that decisions can be taken only at a local level, but all agree on the importance of a joined up approach - which involves GPs, specialist centres, families and community outreach teams.
In some areas this is happening already. In Haywards Heath, West Sussex, the new Chalkhill centre recently opened for the treatment of acute mental health problems.
Under the same roof, young patients have access to a range of services - from education and sporting activities to treatment itself.
There are in-patient beds for admitting the most serious cases, but the focus is on spotting problems early.
Tim Gillett, the psychiatrist at Chalkhill, said: "We want to put resources at an earlier level. We also want to develop community resources. That's our strategy."
It is something the government says it wants to support. Funding for child and adolescent mental health in England has increased substantially. A national advisory council has been set up to address the transition from child to adult services.
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