QEEG almost consistently reports an abnormal excess of delta/theta activity, reduced alpha activity and posterior excess of beta activities in schizophrenics. LORETA allows more precise localization of these findings (excess of delta in bilateral anterior cingulate, increase of beta in parietal gyrus).All antipsychotic drugs induce significant changes in QEEG reflecting differential effects on inhibitory and excitatory activities. Two QEEG profiles of first-generation antipsychotics may be differentiated: a)chlorpromazine-type profile, characterized by an increase in delta/theta and a decrease in alpha and beta power spectra, and b)haloperidol-type profile, which exhibits no significant change in delta/theta frequency band but increase of alpha and alfa adjacent beta activity. The second generation antipsychotics have different QEEG and LORETA profiles probably reflecting their different mechanism of action. Clozapine produces an increase of delta, theta and alpha1 and decrease of alpha2 and fast beta activities. Comparing to antipsychotic-naïve schizophrenics, clozapine-treated patients showed an excess of delta and theta activities in anterior cingulate and medial frontal cortex. QEEG profile of olanzapine is similar to clozapine, whereas tomography show slightly different pattern (decrease of alpha1-beta activities in the occipital cortex and posterior limbic structures and decrease of beta3 sources in the fronto-temporal cortex and anterior cingulum). Risperidone increased current density in frontal regions for delta, theta and alpha1 in healthy subjects, whereas we found no changes in LORETA between risperidone-treated and antipsychotic-naïve patients. According to‘key–lock principle'the pharmaco-EEG topography and tomography could be helpful in the optimization of antipsychotic therapy.

Supported by the projects IGA MZCR NR9330-3/2007 and MSMTCR1M0517.