Why Ketamine Immobilizes Some Users NYT: Science By: Andrew Jacobs 10 October 2026 at 16:38 Potent powders can produce a nearly catatonic state, particularly in those who have not tried the drug before. Β© Sandy Huffaker for The New York TimesKetamine is a useful sedative and antidepressant at light doses. At stronger doses, it is a powerful anesthetic, but at repeated high doses, it deadens sensation, leaving users conscious but unable to act.