Too many young offenders have insufficient access to healthcare, particularly the large proportion needing mental health services, health and probation watchdogs have said.
The Healthcare Commission and HM Inspectorate of Probation has published a report examining 50 out of 155 youth offending teams (YOTs) in England and Wales.
It found that one in six YOTs did not have a healthcare worker, even though primary care trusts (PCTs) have a statutory duty to provide one.
A third of YOTs did not have a mental health worker, even though 40% of child and young offenders have emotional or mental health needs.
Healthcare Commission chief executive Anna Walker said: "The consequences of not providing support to these children are dire for the young person and the local community.
"Children and young people are responsible for 25% of all crimes in the UK and 40% of those who commit crimes have mental health problems."
The NHS has a "significant" role to play, she said.
She added: "All primary care trusts must fulfil their statutory duty to provide healthcare workers to their local youth offending teams."
A statement from the Youth Justice Board for England and Wales welcomed the report, which it said, "highlights the good practice and commitment of health and substance misuse workers attached to YOTs in England and Wales.
"While the majority of YOTs have successfully developed positive health services supported by significant investment by the Department of Health into local Child and Adolescent Mental Health Services, the report highlights areas of concern that need further work between Youth Justice and Health partnerships at a national and local level."
