Journal of psychopharmacology (Oxford, England)
June 30, 2025
Jess Kerr-Gaffney, Anna Tröger, Alice Caulfield et al.
6 citations
Ketamine, a rapid-acting treatment for depression and other psychiatric conditions, has raised safety concerns because chronic recreational use can damage the bladder and urinary tract. This systematic review of 27 clinical studies, mostly in people with depression, found that 0% to 24.5% of patients receiving ketamine reported urological symptoms, which were usually mild or moderate. Objective measures of bladder and kidney function showed no significant changes from before to after treatment. The evidence suggests that therapeutic ketamine does not appear to increase the risk of urological problems, but most studies were short-term and did not systematically monitor symptoms, so more long-term research is needed.
Journal of Psychopharmacology
December 26, 2025
Alice Caulfield, Allan H. Young, Mitul Mehta
2 citations
Psychedelics may produce lasting behavioral and clinical change by enhancing learning mechanisms. This narrative review synthesizes evidence across behavioral, neural, and computational levels, proposing that viewing psychedelic mechanisms through the lens of learning unifies context-dependent outcomes, increased environmental sensitivity, and neuroplastic change. Persistent changes in top-down and bottom-up information processing at a systems-level may account for both therapeutic and adverse effects, converging with the reopening of critical learning periods. This systems-level framework explains why outcomes vary widely and depend on context: the learning environment—including psychological support and therapeutic insights—shapes lasting effects. Understanding these mechanisms has translational relevance for psychedelic-assisted psychotherapy.
Journal of psychopharmacology (Oxford, England)
June 16, 2026
Alice Caulfield, Matthew Butler, Mitul A. Mehta
Psychedelics show promise for treating neuropsychiatric conditions, but their Schedule 1 status creates regulatory and economic hurdles for research. Rigorous human mechanistic studies are needed to understand how psychedelics produce therapeutic effects. This article offers practical guidance on study design, legislation, and drug sourcing, based on the authors' experience setting up non-clinical studies in the UK. The guidance aims to help researchers navigate the complex process of establishing human psychedelic studies, with some content applicable to investigator-initiated studies more broadly.
bioRxiv
July 22, 2025
Alice Caulfield, Lorraine Li, Famia Askari et al.
preprint
Psychedelics show potential for enhancing associative learning in animals, according to a systematic review of 31 studies (29 animal, 2 human). The review found that psychedelic administration improved learning across classical and operant conditioning paradigms, including fear extinction and reversal learning, though effects varied by dose, timing, training intensity, and sex. Possible mechanisms include increased prediction error sensitivity, serotonin receptor agonism, and structural plasticity. Learning enhancements may persist into the post-acute phase and depend on active environmental engagement. These findings have not yet been confirmed in humans, but suggest a window of enhanced learning that could inform psychedelic-assisted psychotherapy.