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NMDA receptor function and human cognition: the effects of ketamine in healthy volunteers.

A K Malhotra, D A Pinals, H Weingartner, K Sirocco, C D Missar, D Pickar, A Breier

Neuropsychopharmacology May 1996 DOI: 10.1016/0893-133x(95)00137-3 (opens in new tab)

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Study at a glance

AI-extracted from the abstract
Characteristics Double-blind, placebo-controlled trial Peer reviewed
Sample size 15
Population Healthy volunteers
Intervention Ketamine
Dose subanesthetic doses
Duration 1-hour infusion
Topics Esketamine Ketamine
Key findings Subanesthetic ketamine produced decrements in free recall, recognition memory, and attention in healthy volunteers, and briefly induced psychosis-like symptoms. The memory impairments were not accounted for by attention changes and were not significantly related to psychosis ratings, suggesting the NMDA receptor plays a direct role in explicit memory.

Abstract

A rapidly growing body of preclinical data has implicated the glutamatergic N-methyl-d-aspartate (NMDA) receptor in memory and other cognitive processes. There is comparatively less information about this receptor system in human cognition. We examined the effects of subanesthetic doses of ketamine, a noncompetitive NMDA receptor antagonist, on two forms of memory, free recall and recognition, as well as attention and behavior in a double-blind, placebo-controlled, 1-hour infusion in 15 healthy volunteers. Ketamine produced decrements in free recall, recognition memory, and attention. In addition, ketamine induced a brief psychosis in our healthy volunteers marked by thought disorder and withdrawal-retardation. Ketamine-induced memory impairments were not accounted for by changes in subject's attention and were not significantly related to psychosis ratings. These data suggest that the NMDA receptor plays a direct role in two types of explicit memory. The implications of these data for the pathophysiology of schizophrenia are discussed.

Comparable studies

Other randomized controlled trials on ketamine, most cited first.

Study Year Design Participants
Subanesthetic Effects of the Noncompetitive NMDA Antagonist, Ketamine, in Humans Healthy human subjects recruited from the community 1994 Randomized controlled trial n = 19
Antidepressant Efficacy of Ketamine in Treatment-Resistant Major Depression: A Two-Site Randomized Controlled Trial Patients with treatment-resistant major depression experiencing a major depressive episode 2013 Randomized controlled trial n = 73
Remifentanil-induced Postoperative Hyperalgesia and Its Prevention with Small-dose Ketamine Patients undergoing major abdominal surgery 2005 Randomized controlled trial n = 75
Efficacy of Intravenous Ketamine for Treatment of Chronic Posttraumatic Stress Disorder Patients with chronic PTSD related to a range of trauma exposures 2014 Randomized controlled trial n = 41
Ketamine-Induced Deficits in Auditory and Visual Context-Dependent Processing in Healthy Volunteers Healthy volunteers 2000 Single-blind placebo-controlled study n = 20

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Esketamine Ketamine