The current guidelines used for determining mental health treatments are based on flawed evidence and need replacing, the Chief Medical Officer (CMO) has said in her annual report.
Mental illness is the leading cause of sickness absence in the UK, accounting for 70 million sick days in 2013, up 24% since 2009.
Mental illness costs the UK economy between £70-£100billion annually, 4.5% of GDP.
The report by CMO Professor Dame Sally Davies has explored the basis on which current judgements about mental health are reached. In particular she highlighted the nature of well-being as currently judged by policymakers.
Davies said:"In pointing out the lack of evidence for well-being, I have been asked to ‘take a leap of faith' about well-being in mental health. As Chief Medical Officer I will not take a leap of faith with people's health.
"The truth is that well-being in mental health is one poorly evidenced strand of a much bigger picture, and I recommend that bigger picture to
policy makers."
Since the Foresight report in 2008 well-being has been used as a key part of mental health policy development.
That report suggested that a small increase in overall well-being in the population would reduce the amount of mental illness in the population.
Davies' report revealed that much of the research underlying it is not scientifically rigorous but from small or methodologically flawed studies. The report also outlines how patients can be considered as both suffering from a mental illness and having a good level of well-being.
The report recommended the adoption of the World Health organisation's guidelines on mental illness which emphasis three key aspects, mental health promotion, mental illness prevention, and treatment and rehabilitation.
This would mean an end to considering well-being as a distinct objective and encouraging evidence based policies. The report also encouraged an increase in occupational healthcare, which currently covers less than 30% of employees.
The majority of evidence about mental health well-being is limited to studies of children and young people and that this evidence has been incorporated into guidelines for treatment already the report added.
An emphasis on interventions which are proven to be effective is recommended, along with work to make an effective definition of what well-being is.
Professor Sheila Hollins, chair of the BMA's Board of Science, said, "This new report highlights the need for urgent action to ensure equal value is placed on both patients' mental and physical health."
She added, "We are encouraged by this report and will continue to call for equal treatment for both physical and mental health patients, the reduction of waiting times for mental health patients, and the introduction of equal funding between mental health services and other NHS services."