Clin Psychopharmacol Neurosci.  2011 Aug;9(2):78-85.

Effects of Psychotropic Drugs on Quantitative EEG among Patients with Schizophrenia-spectrum Disorders

  • 1Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea.
  • 2Department of Neuropsychiatry, The Armed Forces Capital Hospital, Seongnam, Korea.
  • 3Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine & Institute of Human Behavioral Medicine, Seoul National University, Seoul, Korea.


We examined how psychotropic medications affected quantitative EEG (qEEG) results among patients with a schizophrenia-spectrum disorder.
The drugs were clustered into nine groups depending on their mechanism. We hypothesized that drugs would affect the relative power shown in qEEG results independently and investigated the effect of each drug group on relative power using multiple linear regression analysis and independent samples t-tests.
We found that antipsychotics other than clozapine induced an increase in the relative power of alpha activity. Clozapine markedly increased slow waves and decreased alpha activity in the occipital area. The main findings for antidepressants and antiepileptic drugs were the beta increment and lithium increased the power of delta and theta activity. However, we found no evident changes in power due to benzodiazepine.
Our results are generally consistent with previous pharmaco-EEG studies, despite some differences. Therefore, the EEG effect in each drug group could be singled out even under the polypharmacy condition, with the possible exception of benzodiazepines. Our results support using a new methodological approach to identify the qEEG effects of various psychotropic drugs in clinical settings.


Pharmaco-EEG; Polypharmacy; Psychotropic drugs; Quantitative EEG; Relative power; Schizophrenia-spectrum disorder
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