Negative symptoms in neuroleptic-naïve patients with first-episode psychosis correlate with QEEG parameters

INTRODUCTION: While several studies have shown an association of QEEG band power with negative symptoms in patients with schizophrenia, this has not yet been investigated in a sample with neuroleptic-naïve first-episode patients (NNFE) up to now. From literature we hypothesized delta (0.5-4Hz) and theta (4-8Hz) power to be augmented and alpha (8-12Hz) power to be decreased with increased negative symptoms in NNFE. MATERIALS AND METHODS: The sample consisted of 27 NNFE. Psychopathology was rated with the Scale for the Assessment of Negative Symptoms (SANS). EEG was recorded from 21 electrodes according to the 10/20 system. Spectral analysis was performed on mean power of 8 electrodes in seven frequency bands after artefact removal. Linear regressions were calculated with log transformed power as dependent and psychopathology as independent variable. We controlled for medication, drugs, age, sex, education and day time of EEG recording. RESULTS: A positive correlation of SANS global score with power in delta and theta frequency bands could be confirmed in NNFE. In the alpha1 (8-10Hz) band we found no significant correlation with negative symptoms and in the alpha2 (10-12Hz) band there was a positive correlation with SANS (p=0.069). Beta1 (12-15Hz) power also correlated positively with SANS. DISCUSSION: The present results confirm the correlation of negative symptoms with power of slow frequency bands. In addition to previous studies in chronic schizophrenia patients, the effect was shown in NNFE, which is compatible with augmented slow wave power being a marker for negative symptoms in psychosis.