One million more people a year with mental health problems will receive treatment in England by 2021, the NHS has pledged.
The move comes after a new report found only 15% of people who need psychological therapy in England get access to care, despite mental health problems representing the largest single cause of disability in the UK and suicide rates in England rising after years of decline.
The report also shines a light on problems for children - one in ten of whom have a diagnosable mental health condition.
Children and adolescents can be sent "anywhere in the country" for inpatient treatment, forcing families to travel long distances, and in some areas one in ten of children's appointments are cancelled because of staff shortages, the report found.
As well as a rising suicide rate that peaked in 2014 at 4,882 deaths, the number of people being detained under the Mental Health Act is rising year on year.
The leading cause of death for men aged 15-49 is suicide and a quarter of people who took their own life had been in contact with a health professional, usually their GP, in the last week before they died.
Suicide is also the second leading cause of maternal death, after cardiovascular disease, but only 15% of areas have the right perinatal mental health services and 40% have none at all.
A focus on care for new mothers also aims to see at least 30,000 more women a year receive access to specialist perinatal mental health services which are currently only available in 15% of areas.
The plans, set out on Monday in the Mental Health Five Year Forward View, will be funded by an extra £1 billion a year from the NHS by 2020-21.
The report authors - an independent task force led by Paul Farmer, the chief executive of Mind - have suggested integrating physical and mental health care and taking steps to ensure that people facing a crisis should have access to mental health care seven days a week and 24 hours a day.
Mr Farmer said: "Mental health services have been underfunded for decades and too many people have received no help at all, leading to hundreds of thousands of lives put on hold or ruined, and thousands of tragic and unnecessary deaths."
The report - which put the cost of mental ill health to the economy, NHS and society at £105 billion a year - recommends actions to help one million more people a year, 280,000 of whom are those with severe mental health problems who will have their physical health needs met.
At the moment, 24/7 community-based mental health crisis care is only available in half the country, but by 2020-21 home treatment for patients in crisis should be available all over England and every acute hospital will have mental health liaison services in emergency departments.
The recommendations come as a survey of GPs by Pulse magazine showed 58% of GPs say they have to diagnose child and adolescent mental health "above their level of competence" due to a marked deterioration in access to specialist services.
Health Secretary Jeremy Hunt said: "We have made monumental strides in the way we think about and treat mental illness in this country in the last few decades - from a society that locks people away in asylums to one giving mental health equal priority in law.
"But we must accelerate progress even further. Our shared vision of a seven-day mental health service means people will get the care they need, when they need it, and will help us do much more to prevent mental illness in the first place."
Shadow minister for mental health Luciana Berger said: "It is very welcome that NHS England has listened to this independent task force and is committing to reforms and additional investment that our mental health services desperately need.
"If implemented in full, these changes could make a significant difference to a system which has had to contend with funding cuts and staffing shortages at a time of rising demand, leaving too many vulnerable people without the care they need.
"The real challenge will come in ensuring these recommendations are actually delivered. For too long this Tory Government's rhetoric on mental health has not matched the reality on the ground. For the thousands of patients who have been left to struggle without the right support, ministers must keep their promises and deliver these vital reforms that are long overdue."
Unison head of health Christina McAnea said: "The provision of mental health services in this country is in a dire state. It is hard to imagine how much worse things can get when children are being sent far away from their families because of a lack of bed and when too may adults harm themselves because they are not receiving the help they desperately need.
"This report rightly highlights the urgent and immediate need for extra funding to save services. The Prime Minister has so far failed to live up to his pledge to prioritise mental health. So we are renewing our call to the government to find new money to ensure no one with mental health issues is left to suffer alone."