How do psychedelic drugs work on the brain?

Dr Robin Carhart-Harris tackles the difficult question of how certain drugs produce hallucinogenic qualities in our brains.


Dr Robin Carhart-Harris talks about his scientific research into the effects and potential therapeutic uses of psychedelic drugs. Join him as he discusses brain imaging work involving psilocybin, the active ingredient of magic mushrooms, and explains how the drug works in the brain.


  • Decreased blood flow in the brain’s main transit hubs
  • Decreased integrity of key brain networks
  • Collapsed rhythmic structure of cortical activity
  • Hyper-excitable prediction units causes impetuous inference
  • Normally distinct brain networks become ‘one’
  • Network stability becomes fleeting

About Dr Robin Carhart-Harris

In 2005, Robin began a four year PhD in Psychopharmacology at the University of Bristol. In 2009, he successfully coordinated the first clinical study of psilocybin in the UK and the first clinical study of a classic psychedelic drug in the UK for over 40 years. Also in 2009, Robin moved to Imperial College London to continue his work under the supervision of Professor David Nutt. Robin has since coordinated the first resting state fMRI and MEG investigations of a psychedelic drug and the first fMRI study of MDMA in the UK. Robin and David Nutt recently received ethics approval for an MRC-sponsored clinical trial that will investigate the efficacy of psilocybin as a treatment for depression and an LSD fMRI and MEG study. Robin’s work is published in PNASBrainSchizophrenia Bulletin and the British Journal of Psychiatry and he has appeared in television interviews for BBC news and Channel 4.

He also made an appearance in the recently released Reason TV’s Psychedelic Science: Rediscovering Magic Mushrooms episode.