Psychological effects of ketamine in healthy volunteers. Phenomenological study.
Edith Pomarol‐Clotet, Garry D Honey, G K Murray, Philip R. Corlett, A R Absalom, M Lee, Peter J. McKenna, Edward Bullmore, P C Fletcher
The British Journal of Psychiatry August 1, 2006 DOI: 10.1192/bjp.bp.105.015263 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Peer reviewed |
|---|---|
| Sample size | 15 |
| Population | Healthy volunteers |
| Intervention | Ketamine |
| Dose | 200 ng/ml |
| Measures | Present State Examination, Thought, Language and Communication Scale, Scale for Assessment of Negative Symptoms |
| Topics | Ketamine Esketamine |
| Keywords | Central nervous system Humans Perceptual disorders Hallucinations Psychoses, substance-induced Infusions, parenteral Delusions Cognition disorders Mood disorders Interview, psychological Adult Middle aged Female |
| Key findings | Ketamine produced perceptual distortions but not hallucinations, with referential ideas in nearly half of 15 healthy volunteers and only mild, infrequent thought disorder ratings. The authors conclude ketamine does not reproduce the full picture of schizophrenia; the main similarity is referential thinking, and apparent negative symptoms may reflect sedation rather than a schizophrenia-like effect. |
Abstract
Background: The psychosis-inducing effect of ketamine is important evidence supporting the glutamate hypothesis of schizophrenia. However, the symptoms the drug produces have not been described systematically.
Aim: To examine the effects of ketamine in healthy people using a structured psychiatric interview.
Method: Ketamine (200 ng/ml) or placebo was administered by continuous infusion to 15 healthy volunteers. Symptoms were rated using the Present State Examination, the Thought, Language and Communication Scale and the Scale for Assessment of Negative Symptoms.
Results: Ketamine induced a range of perceptual distortions, but not hallucinations. Referential ideas were seen in nearly half the sample. There were only mild and infrequent ratings on the thought disorder scale. Affective flattening and alogia were seen in some volunteers.
Conclusions: Ketamine does not reproduce the full picture of schizophrenia. The main point of similarity concerns referential thinking. Phenomena resembling negative symptoms are also seen, but the distinction of these from the drug's sedative effects requires further elucidation.
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 |
Citations in the library
Cited by 75
- Ketamine and Ketamine Metabolite Pharmacology: Insights into Therapeutic Mechanisms Pharmacological Reviews June 26, 2018
- Mechanisms of Ketamine Action as an Antidepressant Molecular Psychiatry March 13, 2018
- Ketamine for chronic pain: risks and benefits British Journal of Clinical Pharmacology February 21, 2013
- From drugs to deprivation: a Bayesian framework for understanding models of psychosis Psychopharmacology May 27, 2009
- Ketamine: 50 Years of Modulating the Mind Frontiers in Human Neuroscience November 29, 2016
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Cites 8
- Subanesthetic Effects of the Noncompetitive NMDA Antagonist, Ketamine, in Humans Archives of General Psychiatry March 1, 1994
- Recent advances in the phencyclidine model of schizophrenia American Journal of Psychiatry October 1, 1991
- Study of a New Schizophrenomimetic Drug—Sernyl Archives of Neurology And Psychiatry March 1, 1959
- Measurement of dissociative states with the Clinician‐Administered Dissociative States Scale (CADSS) Journal of Traumatic Stress 1998
- Psychedelic Effects of Ketamine in Healthy Volunteers Anesthesiology 1998
and 3 more in the library