James Halpern

James H. Halpern is a clinical researcher whose work sits at the intersection of psychopharmacology, neuropsychology and psychedelic epidemiology. He has led and co-authored multiple observational, neurocognitive and clinical case-series studies addressing the health and safety of sacramental hallucinogen use (notably peyote in Native American religious contexts), the psychological and cognitive sequelae of long‑term peyote exposure, and residual neurocognitive features in long‑term MDMA (ecstasy) users with limited exposure to other drugs.

Halpern has also contributed to clinical reports and literature syntheses on the response of primary headache disorders (notably cluster headache) to serotonergic psychedelics such as psilocybin and LSD, and to epidemiological analyses exploring associations between lifetime psychedelic use and prevalence of opioid use disorder. His contributions are characterised by combining standardised neuropsychological assessment, pharmacoepidemiological methods and attention to safety and harm‑reduction, informing contemporary discussions of both risks and therapeutic potential of classic psychedelics.