Convergent increases in serotonin 1B receptor binding following ketamine and electroconvulsive therapy: a multi-centre bayesian re-analysis of PET data
Molecular Psychiatry July 8, 2026 Granville J. Matheson, Johan Lundberg, Martin Gärde et al.
The serotonin 1B receptor (5-HT1BR) can be imaged in living humans using a PET tracer called [11C]AZ10419369 and is linked to major depressive disorder (MDD) and its treatment. Ketamine and electroconvulsive therapy (ECT) are rapid-acting antidepressants that raise serotonin levels, but whether they directly alter serotonin receptors was unclear. Reanalyzing 222 PET scans from three centers—including MDD patients before and after ketamine (19 completers), saline placebo (10), or ECT (13 completers)—using a hierarchical Bayesian method, the authors demonstrate large increases in 5-HT1BR binding after both ketamine (6.4%, 95% CI: 3.1–9.6%) and ECT (9.3%, 95% CI: 4.3–14.2%).