Nicotine Fails to Attenuate Ketamine-Induced Cognitive Deficits and Negative and Positive Symptoms in Humans: Implications for Schizophrenia
Biological Psychiatry, 06/22/2012
Clinical Article
D'Souza DC et al. – At blood levels comparable with tobacco smoking, nicotine infusion does not appear to alleviate the ketamine–induced transient cognitive and behavioral effects in healthy subjects that resemble those seen in schizophrenia. The lack of an effect of nicotine on a spectrum of ketamine effects suggests that the consequences of N–methyl–D–aspartate receptor antagonism are not likely under the direct influence of nicotinic acetylcholine receptor .
Methods- The interactive effects of ketamine and nicotine were evaluated in 37 healthy subjects in a randomized, placebo-controlled, double-blind, crossover counterbalanced, 2 (intravenous ketamine or placebo) × 2 (intravenous nicotine or placebo) design.
- Verbal and visual memory, sustained attention, working memory, response inhibition, emotion recognition, executive function, reaction time, motor function, and speed of processing were assessed once per test day, while negative and positive symptoms, perceptual alterations, and a number of feeling states were measured several times before and after administration of drugs.
- Ketamine induced cognitive deficits and negative and positive symptoms.
- Nicotine worsened immediate recall, auditory working memory, response inhibition, and executive function and serial processing.
- Nicotine decreased (improved) reaction time on the sustained attention and choice reaction time tasks.
- Nicotine did not reduce ketamine-induced cognitive deficits or negative and positive symptoms.
