The UK incapacity benefit bill could be cut by spending more on psychotherapy, a group of economists says.
The report says psychotherapy could help return people to work
The team from the London School of Economics says expanding therapy services would even pay for itself.
The Depression Report, published on Monday, says a course of psychotherapy costs £750 - the same as a month's incapacity benefit and lost tax.
The Department of Health will be testing the calculations by running two pilot schemes.
Depression and anxiety are reported to account for 40% of people who are claming incapacity benefit and unable to work.
Lord Layard is chairman of the Mental Health Policy Group of the LSE's Centre for Economic Performance (CEP), which produced the report.
He says that many of these people could return to good health and employment if psychological therapy courses were extended across the country.
"These courses would prove a huge benefit in terms of people's lives and saving tax payers' money.
"At least half of people with depression or clinical anxiety can be cured completely with less than 16 meetings with the therapist.
"These are terrible afflictions that cripple or diminish people's lives and only a quarter of them are getting treatment."
Lord Layard said there would be great social benefits from treating people with mental health problems.
"We have one million people who are mentally ill and on incapacity benefit. If they were able to work then we would save a lot of money.
"But the treatment doesn't have to be 100% successful to pay off."
According to the CEP, psychological therapy should be made available to all people suffering from depression, chronic anxiety and schizophrenia.
This, it says, is what the guidelines from the National Institute for Health and Clinical Excellence (NICE) prescribe, but are not currently being implemented.
The report also says current provision means people can wait nine months to receive treatment and there should be a proper psychological therapy service in every part of the country by 2013.
This could be done, it suggests, at no net cost and require 10,000 therapists and 250 local services, with 40 new services opened each year till that date.
The report also says:
- There are more mentally ill people on incapacity benefits than the total number of unemployed people on benefit.
- One in six of all people suffer from depression or chronic anxiety, which affects one in three of all families.
- Modern evidence-based psychological therapy is as effective as medication and is preferred by the majority of patients.
The Depression Report has been welcomed by mental health organisations Mind, Rethink, the Mental Health Foundation and the Sainsbury Centre for Mental Health, which have released a joint statement.
"Access to evidence-based talking therapies for those who need them should be as big a priority for the NHS as any other proven and cost-effective treatment," it said.
"NICE guidance has approved Cognitive Behavioural Therapy for depression, some forms of anxiety and for schizophrenia on seven occasions, yet it is still scarce and subject to waiting times that would be unacceptable for any other form of specialist treatment on the NHS."
The group also called on the government to require Primary Care Trusts to implement existing NICE guidance and publish waiting times for psychological therapies.
"Only then will people with mental health problems have any kind of equality with everyone else in the NHS."
Marjorie Wallace, chief executive of the mental health charity SANE said: "We support the LSE's proposals to provide greater access to psychological therapy, and hope we can be involved in providing a solution.
"We have found that even a telephone call can make all the difference to someone in distress."