Why Your Brain is Stuck: The Truth About Psychedelics and Plasticity
What this video covers
On The Dr. Hyman Show, Dr. Mark Hyman interviews Dr. Robin Carhart-Harris, the neuroscientist whose brain-imaging studies of psilocybin, LSD, and DMT helped launch the modern psychedelic research revival. Carhart-Harris explains his “entropic brain” theory — that psychedelics loosen the rigid, canalized patterns he argues underlie depression, addiction, and other disorders — and why one to three guided sessions can produce lasting change where daily medication does not. The two also connect psychedelic psychiatry to metabolic psychiatry, and Carhart-Harris spends significant time on risks, warning against unguided use; Hyman discloses his own past psychedelic experiences along the way.
Key points
- Carhart-Harris traces his path from a teenage LSD experience and training in psychoanalysis to a PhD with former UK government drugs adviser David Nutt, with funding support from Amanda Feilding’s Beckley Foundation, building a program of brain-imaging studies across different psychedelic compounds.
- He lays out the entropic brain theory: psychedelics do not simply switch off the default mode network but scramble its normally regular rhythms — a “data decompression” of consciousness — and he argues most mental illness is “canalization,” the opposite of plasticity, in which people become stuck in reinforced patterns of feeling and behavior that often began as defenses against adversity.
- Carhart-Harris describes the therapeutic effect as a “system reset” back toward default function, which he says is why one, two, or three sessions can have durable effects; his group’s data, he says, show psychological insight and emotional release — often crying — are the strongest predictors of good outcomes, alongside a spiritual component.
- He warns against a naive “one and done” model and what he calls spiritual bypassing, arguing that people with borderline personality patterns might be destabilized by a single huge dose and better served by lower doses inside long-term therapy, and that integration work is essential for benefits to stick.
- Hyman links psychedelic psychiatry to metabolic psychiatry — ketogenic and mitochondrial therapies for schizophrenia and autism, which he frames as fixed brain-energy disorders — while Carhart-Harris pushes back, arguing even schizophrenia is biopsychosocial, that genetic explanations have proven fallible, and that psychological approaches such as avatar therapy for persecutory voices have a role.
- On risks, Carhart-Harris is blunt: impaired judgment under the influence has led to falls and drownings, unguided trips can destabilize vulnerable people and surface buried trauma without support, and he cites an off-duty airline pilot who tried to bring down an aircraft after a mushroom trip left him doubting reality; he insists on set, setting, and a sober sitter, noting these compounds remain illegal outside trials and state programs in Oregon and Colorado.
- He previews his lab’s frontier work: a study giving volunteers psychedelics four times with 15 hours of brain scanning, 12 of them while tripping, to train machine-learning models that decode the content and intensity of a trip from brain activity — potentially letting clinicians titrate dose to an entropy “sweet spot” — plus a planned EEG/fMRI study of 5-MeO-DMT, which Michael Pollan called “the Everest of psychedelics.”
- Carhart-Harris predicts psilocybin therapy will be a licensed medicine for depression within five years and says MDMA may get through for veterans’ PTSD, while cautioning the rollout will be complicated and that bad practice and tragedies will occur if education and integration lag.