Deputy prime minister Nick Clegg plans to ramp up efforts to tackle mental health discrimination and improve services by setting up and chairing a cross-government taskforce.
Senior ministers, including work and pensions secretary Iain Duncan Smith, health secretary Jeremy Hunt and business secretary Vince Cable, will also sit on the taskforce which plans to meet within days.
Speaking at his monthly press conference, the deputy prime minister will announce on Monday that the taskforce will "urgently examine" how it can improve mental health services for young people and help people suffering from poor mental health back into work.
Last month Clegg announced at the Liberal Democrat conference that patients with mental health issues would be given greater priority and waiting time limits from April. He also noted that talking therapy treatments should be made available to individuals suffering from depression within 18 weeks.
Citing a £400m investment in expanding talking therapies, Clegg will highlight the cost of mentall illness to the country, which currently sees £100bn each year lost through treating preventable illnesses, missed working days and benefits.
He will also note that just a quarter of people with a common mental health problem receive treatment while 90% of prisoners have at least one mental health disorder.
Almost half of employers identified stress and poor mental health as major causes of long-term employee absence, according to research carried out by Group Risk Development earlier this year.
Clegg will say: "Mental health affects every aspect of our lives. One in four people in the UK will experience a mental health problem and it costs the country more than £100bn. This is too big an issue for the NHS to deal with alone. The whole of government needs to combine its efforts and pool its resources to help the millions of people whose mental health condition is preventing them from getting on in life.
"For far too long mental health has been in the shadows and many people have suffered in silence as a result. It is time to turn a corner on outdated attitudes and bring mental health issues out into the open. It is time that the whole of society started providing the care and support to those with mental health conditions in the same way that they would to those with a physical condition."
