Effects of ketamine on thought disorder, working memory, and semantic memory in healthy volunteers.
BACKGROUND
The N-methyl-D-aspartate receptor antagonist, ketamine, produces a clinical syndrome of thought disorder, perceptual distortion, and cognitive impairment.


METHODS
We have administered ketamine to healthy volunteers to characterize the formal thought disorder and specific memory dysfunction associated with ketamine. Ten healthy volunteers underwent a double-blind, placebo-controlled, ketamine infusion (0.12 mg/kg bolus and 0.65 mg/kg/hour). Thought disorder was evaluated with the Scale for the Assessment of Thought, Language and Communication. Cognitive testing involved working and semantic memory tasks.


RESULTS
Ketamine produced a formal thought disorder, as well as impairments in working and semantic memory. The degree of ketamine-induced thought disorder significantly correlated with ketamine-induced decreases in working memory and did not correlate with ketamine-induced impairments in semantic memory.


CONCLUSIONS
This study characterizes the formal thought disorder associated with ketamine and may suggest that ketamine-induced deficits in working memory are associated with ketamine-induced thought disorder.
Adler
C M
CM
Experimental Therapeutics Branch, National Institute of Mental Health, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA.
Goldberg
T E
TE
Malhotra
A K
AK
Pickar
D
D
Breier
A
A
D000328:Adult; D001921:Brain / Q000187:drug effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D011939:Mental Recall / Q000187:drug effects*; D008875:Middle Aged; D009483:Neuropsychological Tests; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D012153:Retention, Psychology / Q000187:drug effects*; D013850:Thinking / Q000187:drug effects*; D014705:Verbal Behavior / Q000187:drug effects; D014706:Verbal Learning / Q000187:drug effects*
D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine