Long-term outcome of patients who receive ketamine during research

Adrienne C. Lahti, Dale Warfel, Tamara Michaelidis, Martin A. Weiler, Kristin Frey, Carol A. Tamminga

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Background: To comprehend the pathophysiology of schizophrenia and to facilitate drug discovery, animal and human models of schizophrenia are necessary. Ketamine, a noncompetitive N-methyl-d-aspartate antagonist, has been used to probe glutamatergic function in normal and schizophrenic volunteers. These studies and others have provided data consistent with a putative involvement of a glutamatergic dysfunction in the pathophysiology of schizophrenia; however, these studies have also raised concerns about the distress inflicted on patients, the potential for adverse events, and the serious long-term effects that could possibly be induced by symptom-simulating action. Methods: For all patient volunteers (n = 30) who participated in these studies, we reviewed the acute safety during and in the immediate postketamine administration. Patients available for long-term follow-up (n = 25) were matched to a group of patients (n = 25) who participated in research but did not receive ketamine. We compared their long-term outcome in terms of psychopathology, the need for psychiatric care, and the amount of antipsychotic medication required for optimal therapeutic response. Results: There were no serious adverse events in more than 90 ketamine interviews. Distress to patients was minimal, which is shown by the lack of anxiety ratings. Over a mean follow-up period of 8 months, we found no differences between patients who did and did not receive ketamine on any measures of psychopathology, psychiatric care, or the amount of antipsychotic medication. Conclusions: In a controlled environment and paying close attention to subject safety features, administering subanesthetic doses of ketamine causes no adverse events and little distress to schizophrenic volunteers. This study strongly indicates that administering ketamine does not change any aspect of the course of schizophrenic illness.

Original languageEnglish (US)
Pages (from-to)869-875
Number of pages7
JournalBiological Psychiatry
Issue number10
StatePublished - May 15 2001


  • Challenge
  • Ketamine
  • Outcome
  • Research ethics
  • Schizophrenia
  • Symptom provocation

ASJC Scopus subject areas

  • Biological Psychiatry


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