Andrew Huberman — Professor of neurobiology and ophthalmology at Stanford School of Medicine and host of the Huberman Lab podcast. This is a solo episode.
The gist
This solo episode breaks down ketamine, a dissociative anesthetic chemically similar to PCP, and its emergence over the past 5-10 years as a treatment for depression, suicidality, PTSD, OCD, and anxiety. Huberman explains the mechanisms by which ketamine works: blocking NMDA receptors on inhibitory neurons to trigger neuroplasticity, releasing and even mimicking the growth factor BDNF, and activating the opioid receptor system. He covers dosing, delivery routes, and how the same-day antidepressant relief is short-lived unless applied in a twice-weekly-over-three-weeks regimen for durable effects. Throughout he balances the clinical benefits against the real risks of abuse, addiction, K-holes, seizures, and death, stressing that drug treatment must be paired with antidepressive behaviors.
Big reveals
- Ketamine and PCP (angel dust) share essentially the same mode of action as dissociative anesthetics, something rarely acknowledged today.
- A Stanford study (Williams, Schatzberg) showed that blocking the opioid system with naltrexone abolishes ketamine's antidepressant effects, implicating the opioid pathway.
- Patients given naltrexone still felt ketamine's immediate euphoria and dissociation but lost the longer-term depression relief, separating the trip from the cure.
- Ketamine itself can bind the TrkB receptor and mimic BDNF, acting like a growth factor in the brain.
- Memantine, another NMDA blocker used for Alzheimer's, has no antidepressant effect, evidence that NMDA blockade alone isn't how ketamine treats depression.
- The combined SR form of ketamine is most potent for depression, S-ketamine second, and a recent trial of pure R-ketamine failed to relieve symptoms.
- As of recording there is zero published clinical evidence that microdosing ketamine helps treat depression.
Things worth remembering
- Monoamine-targeting antidepressants like SSRIs work in only about 40% of depressed people, leaving 60% without relief.
- One landmark study used IV ketamine at 0.5 mg/kg in just seven depressed patients, with relief arriving within 10-15 minutes.
- Ketamine's antidepressant relief can begin the same day yet typically wears off after about 3 days to a week.
- A twice-weekly-for-three-weeks ketamine regimen can produce durable relief lasting months before repeating.
- At 1-2 mg/kg ketamine reaches anesthetic doses, saturating NMDA and mu/kappa opioid receptors.
- Ketamine is metabolized into hydroxynorketamine (HNK), which has high specificity for the mu opioid receptor.
- Only about 25% of orally taken ketamine and ~35% of sublingual ketamine becomes metabolically active, so oral doses must be ~3x injected doses.
- Ketamine abolishes the brain's alpha rhythm and unveils a dreamlike theta pattern during the dissociative state.
- Some users take ketamine rectally to bypass the liver, since ketamine can sharply raise liver enzymes.
- A colleague's line Huberman quotes: 'Better living through chemistry still requires better living.'