Clozapine response and pre-treatment EEG-is there some kind of relationship

Background: Clozapine has been used widely in the management of treatment-resistant schizophrenia. The present study aims at determining whether pre-treatment electroencephalography (EEG) abnormalities would serve as a marker for response to clozapine treatment. Subjects and Methods: This was a cross-sectional study done in a tertiary care center in Mumbai where patients diagnosed with schizophrenia using DSM-IV criteria and resistant schizophrenia using Kane criteria were assessed using EEG prior to starting clozapine treatment. They were rated for symptomatic improvement using the Positive and Negative Syndrome Scale (PANSS) along with Clinical Global Improvement for Severity (CGI-S). The results were statistically analysed and presented. Results: 55 out of the 80 patients in the study showed baseline EEG abnormalities. The mean duration of illness in the patients were 2.65 years. Slow wave and background EEG abnormalities were common in pre-treatment EEG. 36.4% patients in the study showed clinical response. Patients with negative symptoms and baseline EEG abnormalities showed better response. Conclusions: The study was circumscribed and had many limitations due to a small sample size. The relation between pre-treatment EEG abnormalities and clozapine response could not be statistically correlated and it could not be ascertained to be a marker for response to clozapine therapy.