Send to

Choose Destination
Neuropsychopharmacology. 1999 Feb;20(2):106-18.

Ketamine-induced NMDA receptor hypofunction as a model of memory impairment and psychosis.

Author information

Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.


N-methyl-D-aspartate (NMDA) glutamate receptor antagonists are reported to induce schizophrenia-like symptoms in humans, including cognitive impairments. Shortcomings of most previous investigations include failure to maintain steady-state infusion conditions, test multiple doses and/or measure antagonist plasma concentrations. This double-blind, placebo-controlled, randomized, within-subjects comparison of three fixed subanesthetic, steady-state doses of intravenous ketamine in healthy males (n = 15) demonstrated dose-dependent increases in Brief Psychiatric Rating Scale positive (F[3,42] = 21.84; p < 0.0001) and negative symptoms (F[3,42] = 2.89; p = 0.047), and Scale for the Assessment of Negative Symptoms (SANS) total scores (F[3,42] = 10.55; p < 0.0001). Ketamine also produced a robust dose-dependent decrease in verbal declarative memory performance (F[3,41] = 5.11; p = 0.004), and preliminary evidence for a similar dose-dependent decrease in nonverbal declarative memory, occurring at or below plasma concentrations producing other symptoms. Increasing NMDA receptor hypofunction is associated with early occurring memory impairments followed by other schizophrenia-like symptoms.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Nature Publishing Group
Loading ...
Support Center