Hippocampal subfield differences in people with and without recreational ketamine use: Insights from multi-modal neuroimaging.
Addiction (Abingdon, England) January 29, 2026 Yi-Hsuan Liu, Chia-Chun Hung, Marc N Potenza et al.
Recreational ketamine use, primarily administered by smoking, is associated with dose-dependent psychiatric symptoms and cognitive deficits. Heavier use correlates with greater psychological distress, especially anxiety and hostility. Users show reduced accuracy on high-load working memory tasks and have smaller left hippocampal volume, most notably in the hippocampal-amygdaloid-transition-area. Functional connectivity between this region and several brain networks is increased and aligns with NMDA-receptor distribution. These findings suggest that chronic, smoking-administered ketamine use selectively affects hippocampal subregions and related circuitry, potentially explaining working memory impairments.