Ketamine effects on EEG and their links to therapy differ across treatment-resistant major depression, post-traumatic stress disorder, and obsessive-compulsive disorder
The International Journal of Neuropsychopharmacology July 6, 2026 Shabah M. Shadli, Neda Nasrollahi, Calvin K. Young et al.
Ketamine at low doses (0.5-1.0 mg/kg I.M.) quickly reduces symptoms in treatment-resistant major depressive disorder (TR-MDD), post-traumatic stress disorder (TR-PTSD), and obsessive-compulsive disorder (TR-OCD), but its neural effects differ by diagnosis. EEG recordings of resting frontal activity before and after ketamine or fentanyl showed that TR-PTSD patients had dose- and band-frequency-dependent power changes (especially alpha at 0.5 mg/kg), while TR-MDD patients showed no such changes. TR-OCD responses differed qualitatively from both. Correlations between EEG power changes and symptom scale improvements varied by band and electrode across different disorder-specific scales. Ketamine's effects and their therapeutic links vary by brain site and frequency band depending on the DSM diagnosis, suggesting disorder-specific systems require a ketamine-sensitive factor to generate the disorder.