Originally from Sheffield, she sparked a row past year when she said many elderly people are "sitting in homes that really are too big for their needs" - and should not expect to pass them on to their children.
The PM will also announce the campaign to train a million people in mental health awareness - Every Mind Matters - launches today, with a pilot in the West Midlands ahead of a national rollout next spring.
"The main contributing factors include relationship problems (with a boyfriend/girlfriend, fighting with a best friend, etc.), family issues (divorce, separation, abuse, conflict, etc.), trauma (loss, grief, abuse, rape, etc.) and school problems (bullying, learning difficulties)".
A dedicated minister for suicide prevention will be appointed as part of a landmark effort by the Prime Minister to tackle the UK's mental health crisis. But we want to see more.
He added: "We now need to consider collectively what else social media platforms, which have expanded faster than regulations' ability to respond, need to do to help stem the tide of mental ill health in this country and others, or at least help pick up the pieces".
While there has been some progress, the authors urge governments to do more, writing that "mental health now receives less than 1 per cent of global aid".
Chambers says that everyone needs to start addressing mental health among youth before we lose more young people to suicide and before more young people suffer with issues which will follow them into adulthood.