Details of the investigation are still being decided but it will cover  "talking therapies" - including hypnotherapy, counselling and cognitive behavioural therapy.

Confirmation of the proposals came in a written Commons reply   by the Minister of State for Health, Rosie Winterton.

This followed the report by National Director for Mental Health, Professor Louis Appleby – "The national service framework for mental health – five years on " – which looked at the progress achieved since 1999,

Psychological therapies were included in the NSF to reflect their importance alongside drug treatments  "and their popularity with some service users."

Professor Appleby's report – published in December 2004 – looked at the progress achieved over five years in implementing the NSF and gave an undertaking to carry out a review which looked at "the evidence of effectiveness of complementary healthcare for mental health problems."

Previously in 2001 the Department of Health issue guidelines - "Treatment choice in psychological therapies and counselling" -to help GPs and other health professionals understand the range of therapies and what were the most effective for particular conditions.

Hypnotherapy was included among a wide range of disciplines, include EMDR, cognitive analytic therapy, dialectical behaviour therapy and autogenic training.

In a Commons reply to Tory health spokesman Tim Loughton,  Ms Winterton explained: "The review will inform the development of a national framework for supporting local innovation in mental health services to make them more responsive to individual needs."

No firm time-table for the review has yet been decided by the Department of Health but officials were expecting the details to be announced "fairly soon."