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In the standard “things are worse now than ever before” polemic, it's claimed that rates of mental illness are higher now than ever – usually without any proof, and usually alongside known-false claims such as people now being more violent or less healthy (compared to, say, the 1400s).

It seems clear that rates of diagnosis are on the rise, as are disability claims. But can't this just be due to lowered thresholds for diagnosis, and more people seeking treatment? Are there studies that show incidence actually increasing, or an upward trend in psychiatric assessment scores?


Although I've heard this most often amid a laundry list of unsourced (mostly known-false) claims, here's an article in Spring 2005's Ethical Human Psychology and Psychiatry which was later expanded into the book discussed here. It claims that mental illness per 1000 went from 0.2 in 1850 to 20 in 2003.

What I'm looking for in an answer is:

  • Historic prevalences of a few mental disorders with very well-defined symptoms,
  • A good proxy for mental health (e.g., attempted suicide) over at least 50 years, or
  • Repeated applications of a psychiatric assessment scale to groups of people “picked up off the street” at intervals over a total of 25 years or more (not a cohort study; a different group every time).
share|improve this question
How prevalent can a condition be if we cannot diagnose it? – Jonas Oct 25 '11 at 18:40
If one took current diagnostic criteria for a disease and applied them to random populations at different points in history, what would the trend look like? – rdhs Oct 25 '11 at 18:45
Possible dupe of:… – Sklivvz Oct 25 '11 at 18:49
@rdhs: If I had a time machine, I'd probably use it for other things. – Jonas Oct 25 '11 at 18:58
An example: 20-years ago a person saying "I don't feel like working" would be considered lazy, today that person is considered "suffering from depression". – vartec Apr 3 '12 at 14:34

Answer: It's rarely as simple as that.

You suggest picking a couple of diseases.

Well, we have already seen that the story for Autism is far more complicated than just measuring diagnoses per 1000 people.

I figured epilepsy would be a good example of a mental disorder with fairly well-defined symptoms.

First, Professor Sander explains that prevalence depends on whether you are in developed or resource-poor countries. So, there's the first confounding factor.

Second, there are other geographical factors:

There is geographic variation in the incidence of epileptic syndromes likely to be associated with genetic and environmental factors, although as yet causality has not been fully established.

So, that (combined with immigration) is going to make the figures difficult to understand.

Then, he explains that the age groups of the incidences have changed ("a decrease in younger age groups and an increase in persons above 60 years") over time.

But is this just because the population is getting older so the numbers of diagnoses in that age has increased? A poll of people from the street might give a totally misleading result.

In conclusion: There are many different factors that make the underlying question much more complicated than it sounds. Simply asking "Has the number of diagnoses gone up?" doesn't answer anything unless you control for many, many confounding variables like:

  • Population's age
  • Population's immigration
  • Population's wealth
  • Diagnostic techniques (which you did try to control for in the question)
  • Stigma/support attached to diagnosis.
  • etc.
share|improve this answer
I've never thought of epilepsy as a mental illness before.… says that it's "predominantly neurologic and not psychiatric condition". – Gabe Apr 6 '12 at 21:08
@Gabe, oh! I don't deny that epilepsy is neurological (and I am not suggesting it clouds the thoughts of sufferers at any time outside of an attack), but I had always interpreted mental illness to include neurological conditions. If the more common understanding (especially by @rdhs) is that this isn't the case, I'll delete my answer. What's the consensus? – Oddthinking Apr 7 '12 at 0:38
I do believe that rdhs was referencing an article that talks about illnesses that are generally treated with antipsychotics. However, the fact that epilepsy is not treated with such drugs doesn't necessarily invalidate your answer. I'd rather see you change epilepsy to schizophrenia or depression rather than delete your answer. – Gabe Apr 7 '12 at 5:10
Yeah, my first thought for the "specific illness" route was catatonic schizophrenia – something someone would look at and say, "Wow, that person snapped; this is a symptom of a sick society." But for some reason this answer did get me looking at the WHO's US suicide statistics: There's been a 50% rise in the past 50 years, but it's not the 900% (!) suggested, and the rise reflects mostly our aging population and the closing gender gap. If anybody could get the statistics for attempted suicide and take those back to 1850, that'd be an answer. Or else maybe I could get around to it... – rdhs Apr 7 '12 at 9:30
I was afraid schizophrenia and depression diagnosis criteria may have changed, making it more complex to compare. – Oddthinking Apr 7 '12 at 14:19

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