I have seen this quote before but today I received an internal company email with this quote.

The ratio is also cited on page 7 of this 2014 report by Boris Johnson, then Mayor of London:

In any given year, an estimated 1 in 4 individuals will experience a diagnosable mental health condition. A third of these will experience two or more conditions at once

A rate of 25% of people experiencing at least one mental health problem every year would appear to be too high. Just thinking common sense. But then the criteria could be quite low, e.g. feeling a bit sad because a relative has an illness.

I know that mental health charities want to raise the profile of mental health issues and that they do so with the best of intentions, but they do seem to be overstating the case.

What does the evidence say?

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    This seems a bit low on details. Did the company email share anything else on what they considered a "mental health problem"? Or a timeline? Or a location?
    – Erik
    Commented Oct 6, 2022 at 8:44
  • 4
    You could probably find a better source to quote for the claim by looking at the websites of a few mental health charities. On its own, "an internal company e-mail" probably falls short of the site's standard for a "notable claim".
    – IMSoP
    Commented Oct 6, 2022 at 10:08
  • The question states "will experience a diagnosable mental health condition", which is speculative and subjective. OTOH "has experienced a diagnosed mental health condition" would be factual and objective. Commented Oct 6, 2022 at 22:15
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    @WeatherVane note that the linked document actually provides a link to the source of that estimation (page 8): "Psychiatric Morbidity among Adults Living in Private Households, 2000". I assume that study should have a definition of what is considered "diagnosable mental health condition" by its designers. Commented Oct 7, 2022 at 4:08
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    @DanilaSmirnov your link mentions "Citation: Office for National Statistics. (2003). Psychiatric Morbidity among Adults Living in Private Households, 2000." Googling that turns up the actual document: Psychiatric Morbidity Among Adults Living In Private Households, 2000 Commented Oct 7, 2022 at 11:21

2 Answers 2


A similar claim is made by UK mental health charity Mind:

1 in 4 people will experience a mental health problem of some kind each year in England.

They cite an NHS survey from 2007, which includes a more specific figure in its summary:

in 2007 nearly one person in four (23.0 per cent) in England had at least one psychiatric disorder and 7.2 per cent had two or more disorders

One of the attachments on that page is a detailed report of the findings titled "Adult psychiatric morbidity in England, 2007: Results of a household survey. Edited by Sally McManus, Howard Meltzer, Traolach Brugha, Paul Bebbington, Rachel Jenkins"

Section 12, "Psychiatric comorbidity", includes the statistic:

Just under a quarter of adults (23.0%) met the criteria (or screened positive) for at least one of the conditions under study.

From the detailed tables in that section, the conditions covered are:

  • Generalised anxiety disorder (GAD)
  • Mixed anxiety/depressive Disorder
  • Obsessive compulsive disorder (OCD)
  • Depressive episode
  • Panic disorder or any phobia
  • Alcohol dependency
  • Drug dependency
  • Psychosis
  • Borderline personality disorder (BPD)
  • Antisocial personality disorder (ASPD)
  • Post-traumatic stress disorder (PTSD)
  • Attention deficit hyperactivity disorder (ADHD)
  • Eating disorder
  • Problem gambling
  • Suicide attempt in past year

There are specific definitions included for each of these; for instance:

Drug misuse is defined by the World Health Organisation as the use of a substance for a purpose not consistent with legal or medical guidelines, for example the non-medical use of prescription medications or the recreational use of illegal drugs.

Note that nicotine addiction is not covered by this section, so somebody who smokes regularly but does not use any other drugs would not be included in the 23% figure.

Similarly, the appendixes explain exactly how "Mixed anxiety/depressive Disorder" and "Depressive episode" were diagnosed, based on a standardised survey called "Clinical Interview Schedule (CIS-R)".

It would of course be possible to pick a slightly different set of conditions, and use different definitions or thresholds, and come to a different number.

It is also worth noting that this statistic is not the main result of this survey, merely a striking figure which has been picked up on. The survey's main aims were to measure correlations, both between the different conditions, and against other factors such as age, sex, and social background.


The word 'diagnosable' easily makes this statement true. Note this doesn't imply anything was actually diagnosed or the person even went to the doctor. It just says if the person were to go the doctor, there is some mental health condition that the doctor could diagnose.

Medical diagnoses are classified, a commonly used system is the ICD-10 catalog. If you click around there for a bit you will find that there are a lot of very specific diagnoses but there are also a number of catch-all descriptions which could be diagnosed in almost anyone.

In summary, just saying a person has a 'diagnosable' condition doesn't actually imply anything worrying about their health on its own.

  • This is a plausible way in which the statistic could be exaggerated, but you haven't presented any evidence that it was exaggerated in this way. You are picking on the wording of one particular example of a claim that has been made with different wording in different contexts, rather than looking at the origin of that claim. I have already listed a source on this page which says "at least one of the conditions under study" - a much more specific claim.
    – IMSoP
    Commented Oct 11, 2022 at 16:10
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    @IMSoP I'm explaining what the statement actually says which is not what people seem to think it means. So it is not that I claim the statistic is exaggerated, the claim by Johnson is sourced to a proper scientific paper so most likely true. But there is no claim that 1 in 4 people 'are mentally ill' or 'have mental disorders' or anything like that. That is how people tend to interpret the statement but that is not what it means.
    – quarague
    Commented Oct 11, 2022 at 17:15
  • I agree that the statement could have a very broad interpretation, but it doesn't actually rule out a stricter reading. And on this page already is a quote from the NHS stating it much more clearly: "in 2007 nearly one person in four (23.0 per cent) in England had at least one psychiatric disorder""
    – IMSoP
    Commented Oct 12, 2022 at 8:28

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