Submitted by okapi-forest-unicorn t3_zilvg3 in askscience
I was just thinking about conditions such as ADD, ADHD, Autism and so on. My sons doctor was saying there is no scans etc. that could to be done see if he has said conditions it’s all based on observed behaviours. Do you think we will ever understand the brain enough to have tests like we do for a broken bone for such conditions?
Scientist have found differences between ADHD (formerly ADD) brains and normal control brains using MRIs.
https://pubmed.ncbi.nlm.nih.gov/33278156/
Unfortunately using MRI scans to medical diagnosis ADHD has not yet been approved by the FDA. This will probably happen in the future, but getting through FDA approval takes years.
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Years ago, I helped write a study protocol and grant proposal for using hyperpolarized, Noble gas MRI to diagnose early-stage autism, but the fundamental approach was so flawed that I wanted no part of it. Indeed, it's hard to develop noninvasive, objective ways to diagnose disorder like these because (a) the changes that occur are not uniform among all people and (b) the means for following possible markers are not well developed.
I know they can predict autism in young infants by studying their eye movement patterns. With a very high success rate. They took control group of no family history of autism and those babies vs familys with autism and those babies. But it wasn’t a brain study as much as a watching eye movement.
Someday probably, but we currently don't understand the functional properties of unaffected brains well enough to reliably determine by a scan alone what is or isn't within the range of normal variation.
Additionally, these scans would be done by a functional MRI machine (basically a recording of brain activity; a regular MRI is more like a soft-tissue XRAY). Unfortunately fMRI machines with high enough resolution to see that kind of detail are few and far between, and fantastically expensive, so that's not a diagnostic route that will be available to most people.
No. No such scans or biomarkers exist. This is true for most psychological conditions, in fact. The broken bone analogy is not quite right, because we do scan the brain to look for lesions (damaged areas), or tumours, or swelling.
The physical basis of most psychological and psychiatric conditions is largely unknown, probably because it is on a much smaller, subtler, and more complex scale than broken bones or biochemical levels.
A brief read here: https://dash.harvard.edu/bitstream/handle/1/29002457/4934408.pdf?sequence=1
Will we have physical diagnosis in the future? Perhaps, but it's worth noting that there is not bright line dividing autism or ADD from non-clinical symptoms. They are the extreme ends of a distribution of behaviour on which everybody lies somewhere. Again, this is true for many psychological conditions.
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Both things put together
It's highly unlikely that normal people in a non-controlled setting will ever get fMRIs at the rate needed for this kind of thing, because insurance isn't covering it, research grants of the scale needed would be wildly expensive, and average people aren't paying tens of thousands for a brain scan for funsies
Unless the tech changes there would need to be another route
Unfortunately not yet, but there are privately-run "diagnostic centers" out there that will charge you lots of money to perform scans and then diagnose various psych disorders based on them. Even though it's not evidence-based.
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My background is Bioanalytical Chemistry, essentially the field that would do such a test. Psychology/psychiatry is described by words and behaviors. Neurology uses quantitative measurements of the brain to understand physiological disease. Right now, they don’t intersect in an analytical sense meaning you can’t detect the conditions you describe making measurements with any tools we have. We don’t have the biochemical understanding and possibly the tools to make such measurements. But you know that already.
Will we get there one day? I believe we will. But we are in the Stone Age. In vivo brain measurements are very rudimentary.
There is a great podcast that describes exactly what you are asking: Karl Deisseroth on Lex Fridman podcast. It is the best podcast I heard in 2022.
Hey the term ADD is outdated and we stopped using it medically in the late 80's. They are considered sub-types of the same problem but we identify them differently now. There are 3 category's we generally use to identify the types under the ADHD umbrella.
Sorry if you already knew this just something I've had to deal with for a few years now and the issue with people not understanding they present differently but are the same (for the most part).
what about cerebral blood flow ?
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Oh that's interesting I didn't know about this study. However, on reading it, rCBF doesn't look precise enough for individual level diagnosis. To rely on that alone would probably yield loads of false positives and miss many true positives. And since people often know they have depression as its symptoms are subjective, a pencil and paper test seems much more efficient.
But perhaps in the future biomarker(s) will prove accurate for psychological conditions.
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Yes, but these are between-group differences. If you pool together the data from a bunch of people with ADHD and compare it to the data of a bunch of neurotypical people, you'll find consistent patterns. But this won't allow you to say anything meaningful about an individual person's scan—it can't be used for diagnostic purposes. The paper you linked describes efforts to use ML to fix this, but so far the results aren't all that impressive. It's not a matter of the FDA standing in the way. The technology isn't ready.
Neuroimaging methods like MEG continue to advance and further aid clinical diagnosis of neurodevelopmental disorders including neurological diseases & ASD. We're pretty close y'all 😊
DuckMySick44 t1_izs90to wrote
A friend told me recently about studies done scanning the brain for autism and for 'being gay' I think they concluded that they can't really find any physical differences that give concrete evidence, I'm sure in the future as we learn more about the brain and neural pathways etc that it will be possible but right now I don't think we can find any fine details like that to make assumptions on