Plans to "transform" attitudes to mental health, with a focus on children and young people, have been announced by Theresa May.
Additional training for teachers, an extra £15m for community care, and improved support in the workplace were among measures announced by the PM.
Mental health experts said more funding was needed to improve services.
Mrs May's speech comes as she outlined her plans to use the state to create a "shared society".
The government says one in four people has a mental disorder at some point in their life, with an annual cost of £105bn.
Figures show young people are affected disproportionately with over half of mental health problems starting by the age of 14 and 75% by 18.
The prime minister said mental health had been "dangerously disregarded" as secondary to physical health and changing that would go "right to the heart of our humanity".
In the speech at the Charity Commission, Mrs May announced:
- Every secondary school to be offered mental health first aid training - which teaches people how to identify symptoms and help people who may be developing a mental health issue
- Trials on strengthening links between schools and NHS specialist staff, including a review of children and adolescent services across the country
- By 2021, no child will be sent away from their local area to receive treatment for mental health issues
- Appointing mental health campaigner Lord Stevenson and Paul Farmer, chief executive of the charity Mind, to carry out a review on improving support in the workplace
- Employers and organisations will be given additional training in supporting staff who need to take time off
- More focus on community care such as crisis cafes and local clinics, with an extra £15m towards this, and less emphasis on patients visiting GPs and A&E
- The reallocation of £67.7m, mostly from the existing NHS digitisation fund, for online services, such as allowing symptom checks before getting a face-to-face appointment
- A review of the "health debt form", under which patients are charged up to £300 by a GP for documentation to prove to debt collectors they have mental health issues
Health Secretary Jeremy Hunt told the BBC care for children and young people was a "black spot" that needed urgent attention as the pressures of social media, cyber bullying and a big increase in self-harming was a "massive worry for parents".
Mental health charity Sane said the plans needed to "be matched by substantially increased funds to mental health trusts" while Mind said it was "important to see the prime minister talking about mental health" but the proof would be in the difference it made to patients' day-to-day experiences.
Dr Sangeeta Mahajan, whose 20-year-old son Sargaar killed himself after being diagnosed with bipolar disorder, said better access to services was essential.
"They don't discharge patients with adequate information," she said. "The doors were closed to us.
"We were told you either go to A&E or your GP and that is the only way you can come back to us.
"We had no direct access back to the specialist services. That is wrong."
Bed shortages have meant some patients have had to travel hundreds of miles for treatment.
Fiona Hollings, 19, was treated in a specialist eating disorder unit for her anorexia in Glasgow - nearly 400 miles away from her family home in High Wycombe, Buckinghamshire.
Raising the profile of mental health
By Hugh Pym, BBC health editor
Mental health campaigners certainly recognise the significance of the latest initiative headed by the prime minister.
Theresa May's focus on mental illness in her first major speech on health will in itself raise the profile of the issue and reaffirm the drive to achieve true "parity of esteem" with physical health.
Promoting mental health first aid training in schools in England illustrates the prime minister's desire to see this as more than an NHS-only issue.
But there is no new Treasury money for the plans. Funding for care is still challenging. NHS Providers, representing mental health and other trusts, predicts the share of local NHS budgets devoted to mental health will fall next year.
Ministers will argue money isn't everything but it remains an unresolved part of the mental health agenda.
Professor Sir Simon Wessely, president of the Royal College of Psychiatrists, welcomed Mrs May's "new and bold vision", but added: "We have a long way to go before mental health services are on an equal footing with those for physical disorders."
Businesses also welcomed the workplace initiatives.
Simon Walker, director general at the Institute of Directors, said employers had "a real role to play" in ensuring the mental health of their workforce.
But while education leaders backed the ideas that focused on young people, they also had concerns.
Malcolm Trobe of the Association of School and College Leaders, said the major problem schools faced was a lack of access to local specialist NHS care and said government plans had to be "backed up with the funding".
Russell Hobby, of school leaders' union NAHT, agreed: "Rising demand, growing complexity and tight budgets are getting in the way of helping the children who need it most."
Liberal Democrat Norman Lamb, a former health minister, said Mrs May was announcing policies already agreed under the coalition government and called it "a puny response" to "cover up for this government's failure" on delivering, while Barbara Keeley, Labour's shadow minister for mental health, questioned why funding was not being ring fenced.
Mr Hunt said the government had endured a "slightly patchy start" with funding, but that with about £1bn more being spent on mental health than two years ago things were "going in the right direction".
In her speech the prime minister also described her wish to create a "shared society", with the state taking a greater role in ending "unfairness".
The emphasis on a "shared society" marks a contrast with her predecessor David Cameron's "Big Society" agenda, which relied on voluntary organisations rather than state intervention.