[anatoly]

There's lots of true things in that post, and it's undeniable that there's been huge broadening of criteria and it's responsible for a lot of the growth in stats. The question is, is it responsible for all of it? To understand that we have to hold severity constant and compare across time.

A recent study tries to define "profound autism" as "nonverbal, minimally verbal, or IQ<50". They found a significant increase in US children aged 8 from 2000-2016 with profound autism. Non-profound autism increased much more, which makes sense given the broadening of criteria. The study is https://pmc.ncbi.nlm.nih.gov/articles/PMC10576490/

Anecdotally, any speech therapist with a long career will likely remark on a local increase of severe autism cases over the last 20-30 yrs. It's not as "skyrocketing" as ASD stats, but prevalence has likely increased substantially.

[genocidicbunny]

I wonder if perhaps the age when people become parents has an affect on this. Anecdotally, many of the people I know of my generation are having kids later than their parents and grandparents did. There's known correlations to different long-term health issues that we do know of that are related to the age of parents, so if there's a rise in average age of parenthood, it could be related?

Kinda spitballing here though.

[chneu]

Nah. It's been shown that older parents run significantly higher risk for all kinds of genetic and birth defects.

Male sperm begins to degrade sometimes around 30 iirc.

People having kids around 40 years old are significantly more likely to have offspring with a ton of issues. People are having kids much later, now.

This isnt my theory. It's been discussed at length and a google will give tons of info.

[robocat]

  Advancing paternal age was not associated with an increase in risk for either Down syndrome or chromosomal disorders other than Down syndrome.

  Multiple neonatal and pediatric disorders have been linked to older paternal ages.  

  The risk of paternal age has been difficult to estimate and interpret because children often have parents whose ages are similar and likely to be confounded.

From "Disentangling the roles of maternal and paternal age on birth prevalence of Down syndrome and other chromosomal disorders using a Bayesian modeling approach" https://bmcmedresmethodol.biomedcentral.com/articles/10.1186...

[roxolotl]

Don't want to deny that your question, is it responsible for all of it, is sill undecided, however this issue is _likely_ due to similar changes in societal factors.

The Mental Health Parity Act passed in '96, and another passed in '08[0]. Together this leads to a significant increase in to those with mental health issues being treated. So while broadening of criteria might not be to blame for what you're discussing, the broadening of mental health care coverage might be.

[0]: https://en.wikipedia.org/wiki/Mental_Health_Parity_Act#Issue... [1]: https://www.ajmc.com/view/the-mental-health-parity-act-10-ye...

[WarOnPrivacy]

> is it responsible for all of it, is sill undecided, however this issue is _likely_ due to similar changes in societal factors.

The changes in medical culture (over just 10y) are why my youngest was diagnosed but my oldest is not.

[sterlind]

my pet theory is that assortative mating concentrates autism. two people who are each slightly on the spectrum meet, they click (because their minds are compatible), get married and have children. the genetic factors involve get concentrated. after a few generations the effect gets really noticeable. it's easier for autistic people to meet, especially with easier travel, large cities and niches.

[didibus]

That study is at risk of the same effects of diagnostic rules, case-finding, service incentives, record linkage and diagnostic substitution as any other. So it can explain the increase shown here as well. That said, you're right, we don't know if there is within that an increase or not being masked. But it's very possible there isn't, or if there is, it's pretty small. Which wouldn't really mandate as much worrying as is happening now.

For me, the question might be, can we get the data in check? Don't want to go another 20 years and still not be able to know the real data because we kept changing the definitions, the rules around diagnosis, who is eligible to be diagnosed, the cost of diagnosis, etc.

[anatoly]

I think the definition of "profound" they chose (nonverbal, minimally verbal or IQ < 50) has much less wiggle room than the broad ASD/autism diagnosis, and also fewer incentives towards inflation. Diagnosis replacement vis-a-vis intellectual disability is still a worry, and I wish there was a way to contrast with an ID stat for the same population.

Overall am in strong agreement with you, the main thing is to nail down data and very little seems to be done towards that. I've followed these studies and articles since 2011 or so with increasing dismay. The headline-grabbing stats of "1 in X" growing every year are next to meaningless, and yet I believe much points towards prevalence of actual condition really increasing. But with scandalously amorphous definitions and abysmal longitudinal bookkeeping we don't know and can't know how much it's increasing and in what subpopulations.

[recursivecaveat]

The post does cover the stats on severe cases as a substitution effect:

> Evidence: Special-education records reveal a decline in “mental retardation” and other diagnosis counts with each uptick in autism during the 1990s. This is observed in many areas, at many points in time.

[squigz]

Am I right in my reading of that study:

- in 2002, 26.9% of the ~2300 cases of autism were 'profound'

- in 2016, it was 24.3% of the ~4800 cases

I must have missed some stuff, but this doesn't seem hugely significant to me?

[anatoly]

If you mean non-signigicant in terms of absolute numbers, these are numbers coming from a small sample of US population (15 metropolitan communities).

[squigz]

I was more trying to understand your claim "They found a significant increase in US children aged 8 from 2000-2016 with profound autism."

[Yizahi]

I'm not a biologist or a doctor, but I suspect that the reason for more people with profound autism is the fact that all developed countries have massively improved rates of saving fetuses in the premature birth events. If my hypothesis is true, it would mean that so called pro-life conservatives are practically causing increased rates of profound autism, by forcing people to save damaged embryos/fetuses. PS: in my limited circle of acquaintances, 2 out of 2 cases of such kids were caused by doctors saving the fetus with direct medical intervention. And according to one of the fathers of such kid, the more advanced countries are moving away from doing that universally to every mother.

[kgwxd]

>any speech therapist with a long career will likely remark on a local increase of severe autism cases over the last 20-30 yrs.

Population growth.

[binary132]

are you saying the population of speech therapists is not growing proportionately to the general populace?

[em-bee]

i have no opinion on whether population growth is a factor, but to make an observation of the growth of cases it wouldn't matter because the therapists probably know each other, so having more therapists in a locality would be included in the observation. there are more cases not because more people come to me, but because i know more therapists having cases.

[binary132]

that still sounds explainable by population growth, maybe