Hemispheric asymmetry and psychopathological dimensions in drug-free patients with schizophrenia.

Several neuropsychological models of schizophrenia have regarded the syndrome as a disorder of the left hemisphere. However, discrepant experimental findings have been reported. It has been proposed that the different psychopathological dimensions of the syndrome are associated with distinct patterns of hemispheric imbalance. The present study was aimed at exploring relationships of psychopathological dimensions of schizophrenia with fronto- and temporo-hippocampal functioning of either hemisphere in 42 drug-free patients with a DSM-III-R diagnosis of schizophrenia. For the negative dimension, an inverse correlation with the performance on a verbal conditional associative task was found, consistent with the presence of a left fronto-hippocampal impairment in this dimension. As to the positive dimension, our results showed a direct correlation with perseveration on a verbal self-ordered pointing task, suggesting a hyperactivation of the left-hemisphere in this dimension. The disorganisation was found to be associated with a faster execution of a spatial memory task, probably reflecting increased perceptual priming and a right temporo-hippocampal disinhibition.

Multilead quantitative EEG profile of clozapine in resting and vigilance-controlled conditions.

Clozapine is the prototype of a new class of drugs, referred to as 'atypical antipsychotics'. As a matter of fact, the antipsychotic activity of the drug was not predicted by the first studies with quantitative electroencephalography (QEEG), which actually reported an antidepressant pattern. All previous QEEG studies carried out in healthy subjects used a maximum of four leads, exploring only the posterior quadrants of the scalp. The present article reports findings of a multilead QEEG study carried out in 16 healthy men under resting and vigilance-controlled conditions. Increases in slow (delta, theta, and alpha1) and decreases in fast (alpha2 and beta) activities were found, corresponding to changes described for chlorpromazine-type antipsychotics. These results are compared with those of earlier studies. It is suggested that changes in the beta frequency range vary across subjects, whereas changes in slow and alpha activity are more consistent and critical for defining the QEEG profile of the drug.

Influence of moclobemide on cognitive functions of nine depressed patients: pilot trial with neurophysiological and neuropsychological indices.

Quantitative electroencephalogram (QEEG) changes induced by the acute administration of moclobemide (200 mg) in patients with major depression include a transient increase in theta-activity, a slight augmentation of alpha-activity and a sustained increase in beta-activity. This QEEG profile distinguishes moclobemide from sedative antidepressants. A 42-day treatment with 400 mg/day of the drug produces a significant decrease in the late positive-complex peak latency of the event-related potentials, suggesting a positive effect on attention and cognitive functions.

CEEG mapping in drug-free schizophrenics. Differences from healthy subjects and changes induced by haloperidol treatment.

A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment.