Delays in discharging young psychiatric patients is costing the NHS millions of pounds, new research has revealed.

An 18-month study of "bed blocking" at a Birmingham hospital found that some adolescents were facing an average delay of 126 days, or four months.

The most common reason for late discharges were problems finding a placement for the youngsters outside the wards.

It says the cost to the NHS was more than £1 million from March 2003 to November 2004. The research is being presented at the Royal College of Psychiatrists' annual conference in Edinburgh today.

The organisation said the study of three adolescent wards at Birmingham's Parkview Hospital showed bed blocking was "a matter of increasing concern for policy makers and clinicians".

Research has previously focused on the problem among older psychiatric patients, it said, despite the fact that bed blocking was just as expensive and counter-therapeutic for younger people.

Dr Shivani Aggarwal, who formerly worked at Parkview Hospital, said: "The scale of the problem has major financial implications and restricts bed availability for new patients.

"There are particular problems with placements funded by social services that require improved working systems and communication. Young people with very complex needs often fall between health and social services, and are the hardest to place."

The conference runs until Thursday.