At any one time, a sixth of the population in England aged 16 to 64 have a mental health problem, according to statistics body NHS Digital.
Whether it is family or friends, neighbours or work colleagues, the chances are we all know someone who is affected.
And bearing in mind the figure leaves out less common conditions and is a snapshot in time, you could easily argue it is even more prevalent than that. Indeed many do.
With Prime Minister Theresa May expected to announce plans to improve care next week, these 10 charts show the extent of the challenge.
1. Problems are on the increase
It seems to be getting more common – or at least among those with severe symptoms. While the proportion of people affected does not appear to have risen in the past few years, if you go back a little further there has certainly been a steady increase.
Evidence from the NHS Digital study in England shows the rise has been driven by an increase in women with illness.
Why is this? Undoubtedly some of it is down to people being more willing to report and admit mental health problems.
Experts point to the way self-harm in particular is recognised in a way it was not 20 or 30 years ago.
But it is also clear 21st Century life is taking its toll on some people. Economic uncertainty, social media, the influence of the media and rising expectations of what life should be like have all been suggested as possible causes.
2. Women are now more likely to be affected
Women are now much more likely to have a common mental illness.
One in five report they have, compared with one in eight men in England. If you include only those with severe symptoms, the difference is less acute, but still apparent.
See more:bbc.com