Improved p50 auditory gating with ondansetron in medicated schizophrenia patients

Am J Psychiatry. 2005 Feb;162(2):386-8. doi: 10.1176/appi.ajp.162.2.386.


Objective: Most schizophrenia patients have a deficit in auditory sensory gating, which appears to be mediated by the alpha-7 nicotinic receptor, that is not improved with conventional antipsychotic treatment. This study examined the effects of ondansetron, a highly selective 5-HT3 antagonist, on the P50 auditory evoked potential.

Method: Eight medicated outpatients with schizophrenia were given either ondansetron (16 mg) or placebo in a double-blind, placebo-controlled design. Evoked potentials were recorded at baseline and 1 hour, 2 hours, and 3 hours after receipt of drug.

Results: There was a highly significant improvement in P50 gating after ondansetron treatment. The maximal treatment difference was at 2 hours posttreatment (ondansetron: mean=41.4%, SD=39.7%; placebo: mean=80.2%, SD=21.3%).

Conclusions: Ondansetron significantly enhanced P50 auditory gating in schizophrenia patients treated with typical antipsychotics.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acoustic Stimulation
  • Adult
  • Antipsychotic Agents / therapeutic use*
  • Cross-Over Studies
  • Double-Blind Method
  • Drug Therapy, Combination
  • Evoked Potentials, Auditory / drug effects*
  • Female
  • Humans
  • Male
  • Ondansetron / pharmacology*
  • Ondansetron / therapeutic use*
  • Placebos
  • Receptors, Nicotinic / drug effects
  • Schizophrenia / diagnosis
  • Schizophrenia / drug therapy*
  • Serotonin Antagonists / pharmacology*
  • Serotonin Antagonists / therapeutic use*
  • Treatment Outcome


  • Antipsychotic Agents
  • Placebos
  • Receptors, Nicotinic
  • Serotonin Antagonists
  • Ondansetron