In the EU at least 83m people (27%) suffer from mental health problems.
Research agrees that 27% of Europeans experience at least one mental disorder in a year. Population growth means it's probably over 120m people by now.
"In the EU at least 83 million people (27%) suffer from mental health problems (16.7 million in the UK)."—graphic on the Victoria Derbyshire show, BBC Two
The programme attributed these numbers to the Mental Health Foundation, which has taken the 27% and 83 million figures from a 2005 academic study looking into the prevalence of mental health problems in a given year.
It's difficult to know how representative these figures are of the UK population, although in the absence of other evidence they may give a relatively good indication. A few years ago the Foundation seems to have applied that 27% figure for the EU to the (then) population of the UK to get a figure of about 16.7 million people.
A 2011 update to the 2005 research once again found that 27% of Europeans experience a mental health condition in a given year, although because the population of the EU has grown and because the study covered a wider age range the estimate for the number affected went up from 83 million to 118 million. Given that more time has elapsed since then, and the EU's population continues to grow, the number affected will now likely be even higher.
Figures depend on what you count as a mental disorder
The updated study illustrates that what's counted as a mental disorder has a bigimpact on the figures, with their estimate of "mental disorders and other disorders of the brain" rising to 38% when conditions such as ADHD and dementia are included.
The later study found that in a 12-month period 27% of people in Europe—27 EU member states plus Switzerland, Iceland and Norway—are expected to experience at least one of a lengthy list of illnesses, from alcohol and drug dependences to bipolar and psychotic disorders.
It found that 38% of people would have experienced at least one of these, or a further set of conditions. These included borderline personality disorder, attention deficit disorder (ADHD), and dementia.
It's difficult to know how similar these figures are likely to be to the UK population
The researchers themselves admit that generalising their EU-wide findings to smaller populations might be "problematic", with the prevalence of substance abuse being particularly likely to vary across countries. On the whole, though, they didn't find very much variation across countries for most of the conditions, although this wasn't the research question they were setting out to answer.
UK-specific research, as we've seen in the past, isn't able to tell us how many suffer from mental health disorders in any one time period. It does indicate a figure of about one quarter of people screening positive, in a variety of time frames, for a list of disorders broadly similar to the ones encapsulated in the 27% estimate for the EU.