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Comment by dubhrosa | Hacker News Reader

Genuine question: has there been any study that actually measured the "levels" of neurotransmitters in the brain and correlated them with the subjects' behavior? Has there been any study that actually demonstrates what the normal levels of these chemicals are in adults and children, and what the normal range is, and what environmental and nutritional factors can influence them? I ask because I constantly hear the "chemical imbalance" explanation for behavioural issues and prescribing these drugs, but I have not ever found a paper that actually provides scientific evidence for this explanation.

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I wanted to elaborate on that point. You are completely right.

There are laboratories measuring that stuff from urine and saliva. They are expensive and the results also need to be controlled for things like normal thyroid function, so you can map properly derive levels in the brain. Also the tests need to be done at different times of the day.

The test-results include ranges. Interpreting and correlating the values and if they are problematic is the work of the few doctors who work with these labs. A bit like with cholesterol levels in the blood.

A doctor once told me that you can't tell for sure, and there are complete surprises, but normally, if she sees a result-sheet she can give a relatively accurate guess about how the person "generally feels" over the day (tired, happy, hungry, anxious, stressed, relaxed, trouble sleeping or not etc.)

What kind of things can they measure from urine and saliva? Can you point at any literature on this, would love to read more about it.

Adrenaline, Noradrenaline, Dopamine, Serotonine, Cortisol, GABA and many more...

Just google "lab test" for these.

The results all talk about tests that measure levels in the urine or blood, not the level in the brain, sorry if I'm being thick, but I don't see any actually measure brain levels.

Parent poster is responding to your question:

> What kind of things can they measure from urine and saliva?

Some of this stuff is hard to measure.

Anything that doesn't cross the blood brain barrier is never going to get many samples due to the invasive procedures needed.

And for more normal blood based measurements, the protocols for measuring change over time requires a number of blood samples taken over time. The more accurate you want to be the more invasive you must become.

All the research I have read uses proxy measures, for example using PET scan and MRI techniques to measure brain activity and trying to infer the neurotransmitters based on glandular activity in the brain.

In the nineties, and and up to about ten years ago, I would hear Doctors mention "chemical imbalance".

Today, I couldn't imagine a medical doctor claiming a person/patient has a chemical imbalance. The truth is they just don't know what causes mental illness, and most mental disabilities.

For awhile, it looked like they could increase dopamine, decrease serotonin, blah, blah, etc. and they were finally getting a handle on these complicated psychological problems.

Well, they were wrong with their chemical imbalance theories, and they are back to speculation--wild speculation in most cases. Out of all the medical specialties, Psychiarty has not made much progress from the 50's. At least they aren't carring around ice picks and severing the frontal lobes though.

The most extreme critics of SSRIs would argue that the alterations to the brain caused by these drugs are severe and irreversible. Another genuine question: what makes us so sure that future generations won't look back at the widespread prescription of brain altering drugs that operate on practically immeasurable and poorly understood mechanisms, as being so different to lobotomies?

Correlation that has stuck with me for 15 years. An acquaintance of mine stated years ago, when we were in our late 20's, that she was put on SSRIs from 13-17 years old and had absolutely no memories of those years. No recall of her teen years, whatsoever. That struck me as incredibly tragic.

Around the same time another friend was taking a smoking-cessation drug that induced very graphic vusuals of dismembering various family members... but I digress.

This is possible and I'd be surprised if no one has done it. The methodology is to inject subjects with a mildly radioactive drug that has a lower binding affinity for a given receptor than the endogenous ligand (e.g. [11C]raclopride for dopamine receptor occupancy) and then measure how much of this drug is bound to the receptor using PET. If more of the drug is bound, then the level of the endogenous ligand is lower. I don't know much of the literature here, but the technique is well-established and should be substantially more accurate than anything that measures urine or saliva.

> I ask because I constantly hear the "chemical imbalance" explanation for behavioural issues and prescribing these drugs,

EDIT: can I check: are you hearing that from doctors doing the prescribing?

Yes Edit: I also hear it frequently from parents of children who have been referred to psychiatrists by their schoolteachers for (in my opinion at least) fairly minor disruptive behaviour in class; they are repeating what the psychiatrists tell them. The psychiatrists also quote statistics like "half of Swedish inmates are adhd, so if you don't treat your child's adhd there's a good chance he'll end up a criminal (yes really). Here in the UK the diagnosing psychiatrist is also the one that the child must return to twice a year for a checkup at 500 pounds per visit.

So, you haven't actually heard it from the doctors? Because (especially in the UK) any prescribing doctor talking about chemical imbalance for ADHD in children is incompetent.

> Here in the UK the diagnosing psychiatrist is also the one that the child must return to twice a year for a checkup at 500 pounds per visit.

This is false. All treatment is available for free on the NHS. Once they have a diagnosis children don't have to see the same psychiatrist - or any psychiatrist.

https://www.nice.org.uk/guidance/cg72/chapter/1-Guidance#dia...

> 1.3.1.1 A diagnosis of ADHD should only be made by a specialist psychiatrist, paediatrician or other appropriately qualified healthcare professional with training and expertise in the diagnosis of ADHD, on the basis of:

[...]

> 1.5.3.2 Drug treatment should only be initiated by an appropriately qualified healthcare professional with expertise in ADHD and should be based on a comprehensive assessment and diagnosis. Continued prescribing and monitoring of drug therapy may be performed by general practitioners, under shared care arrangements[7].

Yes, I have heard it directly from the doctors, I also hear it repeated by other parents who have kids going through this.

Unfortunately doctors don't follow the official procedures all the time. My experience in the UK does not appear to be an unusual one when I compare notes with other parents.

The treatment may be "free" on the NHS but that doesn't mean the doctor doesn't get paid, and I definitely have direct experience of the diagnosing psychiatrist being the one who is assigned to the child's follow up.

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