Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom; Centre for Academic Mental Health, Bristol Medical School, University of Bristol, United Kingdom.
3 papers in the library · 248 citations · publishing 2013-2022
The medial temporal lobes (MTLs) are specifically involved in how MDMA works in the brain, though more research is needed to understand how the drug's characteristic subjective effects emerge from its modulation of spontaneous brain activity.
Five drugs—cannabis, psilocybin, amphetamine, ketamine, and alcohol—were compared for how well they model psychiatric symptoms. Mental health professionals rated how specific certain experiences were to symptom clusters like depression or psychosis. People with personal drug experience then reported how reliably each drug produced those experiences. No experiences were specific to negative or cognitive psychotic symptoms over depression. Psilocybin best modeled positive psychotic symptoms, while acute alcohol and amphetamine best modeled mania. These findings challenge current assumptions about drug models and point to an understudied area needing more research.
Schizophrenia and drug-induced states from LSD and ketamine both increase neural signal diversity, but they differ in brain connectivity: schizophrenia shows increased information flow from front to back of the brain, while the drugs reduce it. These differences can be modeled by altering Bayesian inference in a predictive processing framework: drug effects correspond to reduced precision of prior beliefs, whereas schizophrenia involves increased precision of sensory information. The findings clarify similarities and differences between these altered states, with implications for understanding consciousness and developing mental health treatments.