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# Your Brain Pays Your Body's Bills: What 200,000 Brain Scans Reveal
- URL: https://longtalkshort.com/paul-thompson-brain-pays-the-bodys-bills/
- Published: 2026-10-24T14:32:56.000Z
- Updated: 2026-10-24T14:32:56.000Z
- Description: Across 200,000 brain scans, neuroscientist Paul Thompson keeps finding the body: weight, hormones, sleep and food all show up in the brain, and some changes fade with treatment. Here's what holds up, what's overstated, and what's a sales pitch.
- Author: Truman
- Tags: Health, Paul Thompson

In brain scans of people with schizophrenia, bipolar disorder and depression, the differences were "far greater" when patients also had obesity or heart and metabolic disease. That finding, from the largest brain-imaging collaboration in the world, is the thread running through this conversation.

Neuroscientist Paul Thompson, who leads the global ENIGMA consortium, tells Mark Hyman that **the state of the body keeps showing up in the brain.** Weight, hormones, sleep and food all leave marks, and **some of those marks fade with treatment.** The science behind that is solid. A few numbers, one dramatic before-and-after story and the episode's sales pitches need a closer look.

*In short: Thompson argues that psychiatric and neurological disorders alike are shaped by heart and metabolic health, and that composite "brain charts" plus blood tests could soon diagnose and track them. The direction is well supported. The ibogaine anecdote, some statistics and the case for scanning healthy people are weaker.*

## 1\. One brain, many labels

Thompson, a University of Southern California professor, describes ENIGMA as about **2,500 scientists in 47 countries pooling some 200,000 scans across more than 30 disorders.**

Imaging first proved itself in Alzheimer's: repeated scans make a "time-lapse movie" of tissue loss spreading from memory to language to planning regions, and drug trials now use that as a readout. A Lilly trial of schizophrenia drugs, he recalls, carried the method into psychiatry.

Structural MRI shows tumors, bleeds and shrinkage; functional MRI tracks blood oxygen as a proxy for activity. His analogy: a pilot over Los Angeles needs the traffic, not just the map. **A depressed brain can look "fine" on a standard scan while its networks switch sluggishly.**

He sorts many conditions into two rough groups:

- **Gas pedal:** "internalizing" conditions, such as depression and the lows of bipolar disorder, show changes in the deep limbic system that drives motivation.
- **Brakes:** compulsive ones, such as addiction, OCD and mania, show changes in the frontal lobes.

Treatments from antidepressants and magnetic stimulation (TMS) to neurofeedback, therapy and diet all try to rebalance networks like the default mode network, which hums along when we ruminate.

![Diagram of Paul Thompson's two-system shorthand: a gas pedal card for the deep limbic system, linked to depression, some anxiety and bipolar lows, and a brakes card for the frontal lobes, linked to addiction, OCD, mania and ADHD. A panel notes that brain differences were larger when people also had obesity or cardiometabolic disease.](https://storage.ghost.io/c/d7/93/d793216c-cf13-441f-bdae-4f3aef998c0e/content/images/2026/10/fig1-4.png)

Thompson's gas pedal and brakes: a simplification, not a diagnostic rule.

## 2\. Treat the body, see it in the brain

The central finding comes via his colleague Tomas Hajek, from ENIGMA's schizophrenia, bipolar and depression data. Some antipsychotics cause weight gain, Hyman adds, which compounds the problem. Thompson likens the brain to **a bank account with more than one way to top it up:**

- **Weight:** overweight people's brains can look about eight years older, he says.
- **Hormones:** low estrogen, testosterone or thyroid hormone tracked with faster brain aging.
- **B vitamins:** those that lower homocysteine have slowed brain shrinkage in trials.
- **Sleep:** the glymphatic system acts as a nightly "car wash" that flushes waste.
- **Nutrition:** ENIGMA's biggest psychiatric brain effect was in anorexia, and those systems recovered once nutrition was restored.

> People shouldn't be so pessimistic.

That's Thompson on the brain's capacity to recover. Hyman offers his own case: after a dinner with former Texas governor Rick Perry, he took ibogaine, a psychedelic, at a clinic in Mexico. He says his quantitative MRI three months later showed cortical thickness up 8 percent and white-matter lesions down 22 percent. (More on that below.)

## 3\. Brain charts, genes and blood tests

**Brain age is a composite score.** Software measures hippocampus volume, cortical thickness, white-matter wiring and blood flow, then compares them with a large reference population, like a pediatric growth chart. Retest after a change and see whether your percentile moves. The reference group has to be diverse, Thompson stresses, or the chart misleads.

![Diagram of a brain chart: a list of inputs such as hippocampus volume, cortical thickness, white-matter wiring, blood flow, blood markers, hormones and genes feeds a growth-chart style plot of brain measure by age, with 5th, 50th and 95th percentile curves, a low first scan and a retest closer to the median.](https://storage.ghost.io/c/d7/93/d793216c-cf13-441f-bdae-4f3aef998c0e/content/images/2026/10/fig2-4.png)

A brain chart, as Thompson describes it: many measures, one percentile, tracked over time. Illustrative, not real data.

**Genes tilt the scales but rarely decide.** Only a small share of Alzheimer's comes from inherited presenilin and APP mutations. For everyone else, APOE4 is the big variant: one copy roughly triples risk, two copies multiply it about ninefold or more, and its effect is weaker in people of African ancestry and stronger in East Asians. His team also matches genetic risk profiles to drugs already on the market.

On blood, he points to amyloid-beta, p-tau217, neurofilament light and GFAP, and predicts that **within five to ten years, scans plus blood markers will diagnose all the major neurological and psychiatric conditions.** His AI4AD project uses AI to split "Alzheimer's" into subtypes, such as Lewy body, TDP-43 or vascular disease, that may need different treatment.

## Weighing it: what holds up

**Solid ground:** a 2020 ENIGMA analysis of 6,420 people linked obesity to thinner cortex, ENIGMA bipolar work found similar effects of body mass, and the 2024 Lancet Commission tied about 45 percent of dementia to 14 modifiable risks, including high blood pressure, diabetes and obesity. But most of this is cross-sectional: it shows association, not that losing weight reverses brain changes.

**Numbers that need context:** the "eight years older" figure comes from Thompson's 2009 UCLA study of just 94 people in their seventies (obese brains looked 16 years older). In ENIGMA's anorexia study, partially weight-restored patients showed partial recovery, not full. About a quarter of people carry one APOE4 copy, but two copies is closer to 2 to 3 percent, not the 6 percent he cites. In the Lilly trial, patients on olanzapine lost less gray matter than those on haloperidol, and whether drugs, illness or both drive that loss is debated. The glymphatic system is well shown in mice, but human evidence is thinner, and a 2024 mouse study found clearance drops during sleep. The B-vitamin benefit was seen in people with memory problems and high homocysteine, and Hyman's mention of keto diets resolving schizophrenia rests on small pilot studies.

**The ibogaine story:** it's one person, with no control and no published scans. An 8 percent jump in cortical thickness would be extraordinary, and white-matter lesions aren't simply "inflammation." Ibogaine can cause dangerous heart-rhythm problems and has been linked to deaths. It is a Schedule I drug in the US, and Mexican clinics work largely outside formal approval. Thompson didn't challenge the claim.

**Testing runs ahead of guidelines:** the first FDA-cleared Alzheimer's blood test, in May 2025, is for people 55 and over who already have symptoms, and expert guidance discourages testing healthy people outside research. The American College of Radiology does not recommend whole-body MRI screening for people without symptoms, partly because of false alarms. Thompson's "what is the downside?" skips that.

**The sales pitch:** Hyman co-founded Function Health, which he pitches repeatedly along with its blood panels and MRI scans. The episode carries ads for BON CHARGE, Paleovalley, Timeline, Seed (whose clinical board Hyman sits on), BIOptimizers and Fatty15, plus his new book and course. The YouTube title promises "the fastest way to reverse brain aging"; the conversation doesn't name one.

## Long Talk Short

- Treat blood pressure, blood sugar, weight and cholesterol as brain care, not just heart care.
- Protect sleep and eat enough. The brain is not sealed off from either.
- An APOE4 result tilts your odds. It is not a diagnosis.
- Alzheimer's blood tests are for people with symptoms. Talk to a doctor before testing when you're well.
- Be wary of single before-and-after scans, including famous ones.

**The one thing to remember:** much of what ages the brain is what ages the heart, and that is the part you can work on today.

Source: The Dr. Hyman Show with Mark Hyman, MD, ["The New Science of Brain Aging: What 200,000 Scans Reveal"](https://www.youtube.com/watch?v=DgzVtVVSBHI&ref=longtalkshort.com) with Paul Thompson, PhD. This is an independent summary of that episode and is not affiliated with the show.

*This article is for general information only and is not medical advice. Don't change medications or try psychedelics such as ibogaine without a qualified clinician. If you're worried about memory, mood or brain health, please talk to a doctor.*