May 22, 2023 • 2hr 32min

Dr. Robin Carhart-Harris: The Science of Psychedelics for Mental Health

Huberman Lab

In this episode, Andrew Huberman interviews Dr. Robin Carhart-Harris, a leading researcher in the field of psychedelic science. Dr. Carhart-Harris is a distinguished professor of neurology and psychiatry at the University of California, San Francisco. His work focuses on how psychedelic compounds like psilocybin, LSD, and DMT affect the brain and can be used to treat various mental health conditions. The discussion covers the history and etymology of psychedelics, their mechanisms of action in the brain, ongoing clinical trials, and the potential future of psychedelic-assisted therapies. Dr. Carhart-Harris provides insights from his groundbreaking research on using psilocybin to treat depression, as well as newer studies on conditions like anorexia and fibromyalgia.

0:00

-0:00

Key Takeaways

Psychedelics like psilocybin and LSD work primarily by activating serotonin 2A receptors in the brain, leading to increased communication between brain regions that don't typically interact
Psilocybin therapy shows promise for treating depression, anorexia, and other mental health conditions, with studies showing up to 67% remission rates for depression
The psychedelic experience itself appears to be important for therapeutic outcomes, not just the neurochemical effects. Key aspects include:
- Using an eye mask to encourage internal focus
- Carefully selected music to guide the experience
- Therapeutic support before, during and after the session
- Encouraging patients to "trust, let go, be open"
Psychedelics can induce an "ego dissolution" experience where one's sense of self becomes less rigid, potentially allowing for new perspectives and insights
Neuroplasticity changes from psychedelics may persist for weeks or months after a session, potentially explaining long-lasting therapeutic effects
Microdosing (very low doses) of psychedelics has not shown clear benefits in controlled studies so far
MDMA therapy for PTSD is furthest along in clinical trials, with potential FDA approval as early as 2024
Psilocybin therapy for depression is in Phase 3 trials, with potential approval around 2026 if successful
Careful regulation and training will be needed as psychedelic therapies become more widely available to ensure safety and efficacy

Introduction

In this episode, Andrew Huberman interviews Dr. Robin Carhart-Harris, a leading researcher in the field of psychedelic science. Dr. Carhart-Harris is a distinguished professor of neurology and psychiatry at the University of California, San Francisco. His work focuses on how psychedelic compounds like psilocybin, LSD, and DMT affect the brain and can be used to treat various mental health conditions.

The discussion covers the history and etymology of psychedelics, their mechanisms of action in the brain, ongoing clinical trials, and the potential future of psychedelic-assisted therapies. Dr. Carhart-Harris provides insights from his groundbreaking research on using psilocybin to treat depression, as well as newer studies on conditions like anorexia and fibromyalgia.

Topics Discussed

Definition and History of Psychedelics (6:03)

The term "psychedelic" comes from Greek roots meaning "mind-revealing"
Coined in 1956 by psychiatrist Humphry Osmond
Refers to compounds that work primarily on serotonin 2A receptors in the brain
"To fathom h**l or soar angelic, just take a pinch of psychedelic" - Humphry Osmond's mnemonic for the term

Mechanisms of Action (46:21)

Psychedelics increase "global functional connectivity" in the brain
This leads to more communication between brain regions that don't typically interact
Correlates with the intensity of subjective psychedelic effects
May persist for weeks or months after a psychedelic session

The Psychedelic Experience (28:28)

Key components of psychedelic therapy sessions:
- Use of eye masks to encourage internal focus
- Carefully selected music to guide the experience
- Therapeutic support before, during and after
Patients are encouraged to "trust, let go, be open"
Early phase often involves anxiety and struggle
Later phases can involve profound insights and emotional release

Clinical Applications (58:45)

Depression: Studies show up to 67% remission rates with psilocybin therapy
Anorexia: Preliminary results from ongoing trial are promising
Fibromyalgia: Early stage trial showing positive outcomes
PTSD: MDMA therapy shows strong results in Phase 3 trials

Microdosing vs Macrodosing (17:32)

Microdosing involves very low, sub-perceptual doses
Popular anecdotally, but lacks strong scientific evidence so far
Macrodoses (e.g. 25mg psilocybin) used in most clinical trials
"This whole microdosing thing, we're kind of waiting for some compelling evidence. As things stand right now, I'd say we lack that compelling evidence." - Dr. Carhart-Harris

Ego Dissolution (2:01:04)

Psychedelics can induce a temporary loss of rigid self-identity
May allow for new perspectives and insights
Contrasts with ego-inflation effects of drugs like cocaine
Linked to activation of serotonin 2A receptors in cortical regions

Integration and Long-Term Effects (1:12:56)

Integration phase after psychedelic sessions is crucial
May involve ongoing therapy, journaling, meditation practices
Some patients maintain benefits for years, others relapse and may need additional sessions
Challenges with current illegality preventing follow-up treatments

Neuroplasticity and Brain Changes (1:19:50)

Single high-dose psilocybin session can induce lasting brain changes
Increased global connectivity persists for weeks
Changes in white matter tracts observed with diffusion tensor imaging
May explain long-lasting therapeutic effects

Legal Landscape and Future Outlook (2:12:26)

MDMA therapy for PTSD likely to be approved first, possibly by 2024
Psilocybin therapy for depression in Phase 3 trials, potential approval ~2026
Many other indications being studied (OCD, addiction, etc.)
Careful regulation and training needed as treatments become available
Concerns about maintaining safety and efficacy as use expands

Conclusion

Dr. Carhart-Harris's research highlights the immense potential of psychedelic-assisted therapies to revolutionize mental health treatment. While challenges remain in terms of regulation, training, and wider implementation, the clinical results so far are extremely promising. As our understanding of these compounds grows, they may offer new hope for conditions that have long lacked effective treatments.

The discussion emphasizes the importance of viewing psychedelic therapy as more than just a drug treatment. The carefully controlled setting, therapeutic support, and the profound subjective experiences induced appear to be crucial components. As these treatments move closer to wider availability, maintaining the integrity of the therapeutic model will be essential.

Overall, psychedelic science represents a potential paradigm shift in psychiatry and our understanding of consciousness. While much work remains to be done, the field is progressing rapidly and may soon offer powerful new tools for healing and personal growth.