Thread by @afshineemrani

1/5
I need to talk to you about what GLP-1 drugs are doing to the brain.
For decades, medicine has treated metabolic health, cardiovascular health, and mental health as completely separate systems. Separate doctors. Separate drugs. Separate departments.
Biology may not work that way.
A landmark study just published in The Lancet Psychiatry is forcing us to reconsider everything.

2/5
Taipale et al. tracked 95,490 people across 13 years of Swedish national data — people with pre-existing depression and anxiety, compared against themselves on and off semaglutide.
44% less worsening depression. 38% less worsening anxiety. 47% less worsening substance use disorder. 44% less self-harm.
Nearly half. Across every psychiatric measure they tracked.
"Ozempic personality" dominated headlines recently — the fear that GLP-1 drugs flatten your ability to feel pleasure.
But if semaglutide stole pleasure at scale, depression would climb.
It fell by nearly half.

3/5
The mechanism tells a different story than the fear.
These drugs appear to quiet compulsive craving without suppressing genuine satisfaction. Less "I need this." Same capacity for joy.
Some of it is likely indirect — better metabolic health, weight loss, lower systemic inflammation, improved sleep, improved mobility, and the psychological impact of finally feeling healthier in your own body.
But there is growing evidence that GLP-1 receptors in the brain's reward and impulse pathways are doing something more direct. Something we don't yet fully understand.
A separate BMJ study following 606,000 veterans found GLP-1 users had 18% less alcohol use disorder, 20% less nicotine dependence, and 25% less opioid use disorder — even in people with no prior substance use history.
These are staggering numbers for a drug class designed to treat diabetes.

4/5
And Eli Lilly is betting the entire next chapter of GLP-1 medicine on this.
They have a once-monthly GLP-1/GIP agonist called brenipatide — and it was never designed for weight loss.
It was designed for the brain.
Phase 3 trials are enrolling right now for alcohol use disorder and smoking cessation. Phase 2 for bipolar disorder, schizophrenia, opioid use disorder, and asthma.
Monthly dosing isn't a convenience feature. It's a clinical necessity. Addiction treatment discontinuation exceeds 50% in the first month with daily medications. A monthly injection changes the math entirely.
If these trials succeed, it's the biggest thing to happen to addiction medicine in a generation.

5/5
As a cardiologist, I see this convergence every day.
The same insulin resistance that drives plaque in your arteries appears to influence addiction, compulsive behavior, mood, and cognitive health. The same inflammation I treat in the cath lab is showing up in the brains of patients with depression and Alzheimer's.
We built medicine around the idea that the heart, the brain, and metabolism live in separate houses. They don't. They share the same plumbing.
We are still early. These are associations — not yet proven causation. Randomized controlled trials are warranted and underway.
But the old walls between body and mind are falling fast. And the potential impact of these medicines keeps getting bigger.