Olanzapine-induced clinical seizure: a case report

Clin Neuropharmacol. 2009 Sep-Oct;32(5):297-8. doi: 10.1097/WNF.0b013e3181a7fd00.


Atypical antipsychotics are known to be associated with electroencephalogram abnormalities. Olanzapine can lower seizure threshold and induce epileptiform discharges. However in patients on olanzapine for the treatment of a primary psychiatric disorder, clinical seizure is a rare occurrence. We report the case of a 25-year-old man with a diagnosis of paranoid schizophrenia with obsessive-compulsive disorder of 8 years' duration who developed new-onset generalized tonic-clonic seizure with exposure to olanzapine. Electroencephalogram showed epileptiform discharges; results of computed tomographic scan and metabolic investigations were normal. His antipsychotic was changed to haloperidol, and the patient showed a significant improvement in psychotic symptoms with no recurrence of seizures and did not require anticonvulsant therapy. Olanzapine has a profile similar to that of clozapine and shares its seizure-inducing potential. Typical antipsychotics such as haloperidol might be a safer option for such patients.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Benzodiazepines / adverse effects*
  • Electroencephalography / drug effects
  • Humans
  • Male
  • Obsessive-Compulsive Disorder / drug therapy
  • Obsessive-Compulsive Disorder / physiopathology
  • Olanzapine
  • Schizophrenia / drug therapy
  • Schizophrenia / physiopathology
  • Seizures / chemically induced*
  • Seizures / diagnosis*
  • Seizures / physiopathology


  • Benzodiazepines
  • Olanzapine