Some studies found that, like other NMDA receptor antagonists, phencyclidine can cause a kind of brain damage called Olney's lesions in rats.[27][28] Studies conducted on rats showed that high doses of the NMDA receptor antagonist dizocilpine caused reversible vacuoles to form in certain regions of the rats' brains. All studies of Olney's lesions have only been performed on non-human animals and may not apply to humans. One unpublished study by Frank Sharp reportedly showed no damage by the NDMA antagonist, ketamine, a similar drug, far beyond recreational doses,[29] but due to the study never having been published, its validity is highly controversial.
Rats. Maybe people, maybe not.