Support services for families with difficult teenagers should continue until the children are 18 years old, according to a report from the children's charity NCH.
The Government's guidance on the Children Act recommends that family support should be provided up to the age of 16.
The NCH report End of my Tether is part of a campaign to improve support to parents. It has been sent out to 300 MPs and peers in an attempt to change family support policy.
"At the moment, family support is withdrawn when the child reaches 16, and many parents are unable to cope without it," said Amanda Allard, senior policy officer at NCH and author of the report.
"The policy is inconsistent with other legislation that says that children do not become adults until they reach 18."
The report found that parents are reluctant to seek professional help because of the stigma attached and do not ask friends or relatives for assistance because they are ashamed of the child's behaviour.
NCH has also produced a supporting leaflet for parents. The report and leaflet are available from the web site at www.nch.org.uk/endofmytether/.