0211 GMT February 16, 2019
Across Europe, it is a point reached somewhere between the ages of 16 and 21, marking the moment at which care from children's services comes to an end, BBC wrote.
A significant proportion are in need of ongoing support and treatment, but among those moving into adult care many report feeling abandoned, neglected or poorly looked after.
Many others fail to get any support at all from adult services — their care reaching a very real cliff edge.
This challenging time often arrives alongside other rapid changes like leaving home, going to university, starting work or beginning new relationships.
What can be done to improve things for them?
'Not ill enough'
The experiences of 1,000 young people leaving child and adolescent mental health services (CAMHS) and entering adult mental health services (AMHS) are being followed in eight European countries: The UK, Ireland, Belgium, the Netherlands, France, Germany, Italy and Croatia.
Their stories are striking and often have common features:
● Being discharged around their 18th birthday and not told about options.
● Being told they are not ‘ill enough’ for adult services.
● Having to persuade adult services that they need help.
● Having decisions made about them, without being involved.
● Having to repeatedly tell their story.
Some young people are unable to attend school, see their friends or even leave their bedrooms.
It is not uncommon for them to wait for appointments with an adult service for a year or more — only to then be told that the service will not accept them, the MILESTONE Project has heard. It is led by the University of Warwick, which is working with researchers in the other study countries.
In the UK — as in many other European countries — mental health problems in children and young people are on the rise, affecting an estimated one in 10 children aged five to 16.
Anxiety and depression are among the most common conditions, with girls aged 14 and above more likely to be affected by these problems than boys. Growing up in a poor household increases the risk of mental illness three-fold.
In the UK fewer than half of young people with mental health problems receive support from their CAMHS service.
Across Europe, the provision of CAMHS varies considerably — from a high of 12.9 per 100,000 young people receiving help in Finland, to 0.5 per 100,000 in Bulgaria.
Being unable to find help can be catastrophic. Nearly one in five deaths among 15 to 19-year-olds in the EU is caused by intentional self harm — second only to transport deaths.
In most European countries support from children's services ends at 18. In some places it is lower, including Cyprus (15-19), Malta (16) and France (16-18). In the UK CAMHS support normally continues until 18.
As many as 75 percent of those in the UK and an average of 33 percent across Europe are considered to be in need of further treatment.
Left untreated, the long-term risks for these young people include poor performance at school, a greater risk of drug and, contact with the criminal justice system and unemployment.