A new report published by charity Action for Children says the emotional needs of children who have been in care are not being well looked after.
The study, Too Much Too Young, suggests issues children bring with them into the care system can often be compounded by their poor experiences while they are in it.
The charity is calling for better ways to meet such children's needs and urges that ongoing support is essential to prevent them following "chaotic pathways".
It says: "Most young people who have been in care continue to cope with the lasting impact of a traumatic childhood. They can suffer from depression and anxiety, on top of dealing with the challenges of living on their own for the first time."
The small-scale research, based on in-depth work with 31 care leavers and 12 professionals working with children in care in England and Wales, lists three key recommendations for the government: to prioritise the emotional and mental health of children in care and care leavers, to keep children safe when they return to their family after care and to continue to support young people when their lives are at their most challenging.