The Liberal Democrats have pledged to invest an additional £11 billion over five years into transforming mental health services.
The party said it would make prescriptions for people with chronic mental health conditions available for free on the NHS among a raft of measures to improve services.
Access to talking therapies would be improved, and new mothers would be given a dedicated maternal, postnatal appointment to tackle under-diagnosis of maternal physical and mental health problems as part of the plans.
The Lib Dems have also pledged to train all teaching staff to identify mental health issues and to ensure all schools provide access for pupil support and counselling.
Luciana Berger, the party's health spokeswoman, said: "Too many people are struggling with their mental health and aren't receiving the support they need.
"The Conservatives have failed to bring forward changes that would see mental health approached with the same urgency as physical health.
"Their manifesto at this election only mentions mental health three times. It is clear that - under a Conservative government - mental health will not be a priority.
"The Liberal Democrats are the party of mental health. We have the most detailed plan to improve mental health services and we will commit £11 billion over five years to make these changes.
"This is at the heart of our plan to build a brighter future for all."