EEG abnormalities associated with antipsychotics: a comparison of quetiapine, olanzapine, haloperidol and healthy subjects

Abstract

In this study the effects of the atypical antipsychotics quetiapine and olanzapine, and the typical antipsychotic haloperidol on EEG patterns were retrospectively investigated in 81 patients under stable monotherapy with either drug (quetiapine: n=22, olanzapine: n=37, haloperidol: n=22). These three subgroups were compared with a control group of healthy subjects (n=30) which were matched regarding sex and age. Diagnoses of patients were schizophrenia (DSM-IV 295.xx, n=61), brief psychotic disorder (DSM-IV 298.8, n=9), schizoaffective disorder (DSM-IV 295.70, n=8) and delusional disorder (DSM-IV 297.1, n=3). There were no statistically significant differences regarding demographic characteristics between the groups. Digital EEG recordings were retrieved from a database and visually assessed by two independent investigators, and one blinded regarding medication. One patient from the quetiapine group (5%), 13 olanzapine patients (35%), five of the haloperidol patients (23%) and two subjects of the control group (7%) had an abnormal EEG. Epileptiform activity was observed in four patients (11%) of the olanzapine group, and none in the others. EEG abnormalities were statistically significantly increased with dose in the olanzapine group, in contrast to patients treated with haloperidol, quetiapine or healthy subjects. In conclusion, EEG abnormalities seem to occur rarely in patients treated with quetiapine comparable to the control group, but significantly more often with haloperidol and olanzapine, possibly due to different receptor profiles of these substances. To our knowledge, this is the first electrophysiological investigation comparing the new atypical antipsychotics quetiapine, haloperidol, olanzapine with healthy subjects.

Late-onset seizures associated with quetiapine poisoning

“…A series of 22 patients taking a therapeutic dose of quetiapine demonstrated EEG abnormalities, but none of the patients had epileptiform activity. EEG abnormalities correlated with dose in the olanzapine group in contrast to patients treated with haloperidol, quetiapine, or healthy subjects [9]. Quetiapine poisoning in our case did not have EEG abnormalities.…”

Quetiapine induced myoclonus

“…The reports of finding EEG abnormality in such patients have been contradictory in previous INDIAN JOURNAL OF MEDICAL SCIENCES literature. [1] Another noteworthy fact is that both of our patients were young females, which is in contrast to previous literature. [2,3] Even the previous case report of myoclonus with quetiapine has been reported in an elderly male.…”

“…The technique is extremely simple and, with due care, we believe the method is easily reproduced in the clinical setting. [1,2] Fifteen female and three male patients with ages between 34 and 86 years and a mean age of 57.8 years with grade II lymphedema of lower limbs in its initial phase (within three to four months of onset as reported by the patient) were selected over a two-year period. Grade I lymphedema is deÞ ned as lymphedema that evolves during the day with patients having no signs of the disease after a night's…”

Associations between Patterns of EEG Abnormalities and Diagnosis in a Large Memory Clinic Cohort

“…As expected [3] , the visual EEG analysis of psychiatric diagnoses resembled that of SC, although a normal EEG was slightly less common. Possible explanations for this difference are a higher proportion of patients with a psychiatric diagnosis using antipsychotic drugs [35], or misclassifications of mildly demented patients with depressive symptoms as having a depressive disorder.…”