Using Ketamine to Model Semantic Deficits in Schizophrenia
Erica Neill, Susan Lee Rossell, Sarah McDonald, Nicole R. Joshua, Nicholas Jansen, Celia J. A. Morgan
Journal of Clinical Psychopharmacology October 21, 2011 DOI: 10.1097/jcp.0b013e318234ee1e (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Placebo-controlled double-blind repeated-measures group design Peer reviewed |
|---|---|
| Sample size | 19 |
| Population | Healthy individuals |
| Intervention | Ketamine |
| Dose | 0.8 mg/kg per hour during 80 minutes with approximate target plasma levels of 200 ng/mL |
| Duration | 80 minutes |
| Topics | Esketamine Ketamine |
| Citations | 11 |
| Key points | Ketamine administration produced abnormal reaction times to implicitly presented indirectly related word pairs (greater priming) and reduced accuracy for explicit pairs, while directly related word pair performance was largely similar across ketamine and placebo conditions. The authors conclude that implicit indirect semantic processing is changed under ketamine in a way akin to schizophrenia. |
Abstract
Semantic deficits constitute a core cognitive abnormality in schizophrenia. In the current study, the N-methyl-d-aspartate receptor antagonist ketamine was administered to healthy individuals acutely while they performed semantic processing tasks that included word pairs of differing degrees of semantic relatedness. Two dimensions of semantic processing were investigated: (1) explicit versus implicit processing, that is, unconscious versus conscious processing of semantic relationships and (2) direct versus indirect processing, that is, word pairs that are closely (LION-TIGER) or distantly (LION-STRIPES) related. The immediate effects of ketamine (0.8 mg/kg per hour during 80 minutes with approximate target plasma levels of 200 ng/mL) were examined in a placebo-controlled double-blind repeated-measures group design with 19 participants. It was predicted that ketamine would disrupt access to semantic memory as evidenced in schizophrenia, especially the indirectly related word pairs. In addition, implicit processing and explicit processing were predicted to be differentially affected. Ketamine administration did result in an abnormal performance in the reaction time responses to implicitly presented indirectly related word pairs (ie, greater priming) and reduced accuracy for explicit pairs. Performance on the directly related word pair tasks (both implicit and explicit) was similar across ketamine and placebo conditions, except for the suggestion of abnormal semantic matching in the accuracy data in the implicit task. This study confirms that implicit indirect semantic processing is changed under the influences of ketamine akin to schizophrenia. Future research comparing a schizophrenia group and a ketamine group directly about these tasks is needed to determine the similarity of impairments.
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
Cites 6
- 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
- Measurement of dissociative states with the Clinician‐Administered Dissociative States Scale (CADSS) Journal of Traumatic Stress 1998
- Comparative and Interactive Human Psychopharmacologic Effects of Ketamine and Amphetamine Archives of General Psychiatry September 1, 2005
- Psychological effects of ketamine in healthy volunteers. Phenomenological study. The British Journal of Psychiatry August 1, 2006
and 1 more in the library