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Jin, Yi; Potkin, Steven G.; Kemp, Aaron S.; Huerta, Steven T.; Alva, Gustavo; Thai, Trung Minh; Carreon, Danilo; Bunney, William E.
doi: 10.1093/schbul/sbj020pmid: 16254067
Previous research in clinical electroencephalography (EEG) has demonstrated that reduction of alpha frequency (813 Hz) EEG activity may have particular relevance to the negative symptoms of schizophrenia. Repetitive Transcranial Magnetic Stimulation (rTMS) was utilized to investigate this relationship by assessing the therapeutic effects of stimulation set individually at each subject's peak alpha frequency (TMS). Twenty-seven subjects, with predominantly negative symptom schizophrenia, received 2 weeks of daily treatment with either TMS, 3 Hz, 20 Hz, or sham stimulation bilaterally over the dorsolateral prefrontal cortex. Individualized TMS demonstrated a significantly larger (F 3,33 4.7, p .007) therapeutic effect (29.6% reduction in negative symptoms) than the other 3 conditions (< 9%). Furthermore, these clinical improvements were found to be highly correlated (r 0.86, p .001) with increases (34%) in frontal alpha amplitude following TMS. These results affirm that the resonant features of alpha frequency EEG play an important role in the pathophysiology of schizophrenia and merit further investigation as a particularly efficacious frequency for rTMS treatments.
Naudts, Kris; Hodgins, Sheilagh
doi: 10.1093/schbul/sbj036pmid: 16384876
Men and women who develop schizophrenia are at increased risk, compared with the general population, to engage in violence toward others. The reasons for this robust finding remain obscure. We undertook a review of studies comparing neuropsychological test performance, neurological soft signs, and structural brain images of persons with schizophrenia with and without a history of violence. Our search identified 17 studies. The results are inconsistent and contradictory, mainly due to varying definitions of violence, differences in sample characteristics, and the use of diverse measures to tap the neurobiological correlates of violent behavior. The results suggest, however, that among men with schizophrenia, those who have displayed a stable pattern of antisocial and aggressive behavior since childhood, as compared with those with no such history, perform better on neuropsychological tests tapping specific executive functions and more poorly on assessments of orbitofrontal functions, show fewer neurological soft signs, and display larger reductions in volume of the amygdalae, more structural abnormalities of the orbitofrontal system, more abnormalities of white matter in the amygdala-orbitofrontal system, and smaller reductions in volumes of the hippocampus.
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