What Is Your Brain Doing on Psychedelics?

Psychedelics change consciousness, but the brain mechanisms behind those effects remain unclear. The article centers on the popular “entropy” model associated with Robin Carhart-Harris, which proposes that psychedelics increase brain entropy by loosening the ordered dynamics that normally maintain a stable, self-referential mind. The model is presented as a way to link molecular action to brain networks and to therapeutic outcomes like becoming “unstuck” through increased plasticity. Skeptics argue the science is not settled: different definitions and measurements of entropy in fMRI and other data may produce different results, and some analyses find that entropy increases are limited, measurement-dependent, or do not track subjective experience reliably. The piece also highlights related concepts like transition or control energy, the difficulty of running decisive “entropy manipulation” experiments, and the possibility that expectation and placebo effects may be a major contributor to lasting changes in mood or outlook.