Effects of ketamine on thought disorder, working memory, and semantic memory in healthy volunteers

Biol Psychiatry. 1998 Jun 1;43(11):811-6. doi: 10.1016/s0006-3223(97)00556-8.


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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Brain / drug effects
  • Double-Blind Method
  • Female
  • Humans
  • Ketamine / pharmacology*
  • Male
  • Mental Recall / drug effects*
  • Middle Aged
  • Neuropsychological Tests
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
  • Retention, Psychology / drug effects*
  • Thinking / drug effects*
  • Verbal Behavior / drug effects
  • Verbal Learning / drug effects*


  • Receptors, N-Methyl-D-Aspartate
  • Ketamine