Do high or low doses of anxiolytics and hypnotics affect mismatch negativity in schizophrenic subjects? An EEG and MEG study.
OBJECTIVE
Many studies have demonstrated mismatch negativity (MMN) attenuation in schizophrenia. Recently, investigators have shown that GABAergic inhibitory neurons may regulate MMN generation. Considering that a substantial proportion of schizophrenic patients receive anxiolytics and hypnotics that have affinity to GABA(A) receptors to reduce their comorbid symptoms of anxiety and sleep disturbances, we need to assess whether anxiolytics/hypnotics might affect their MMN generation. The aim of this study is to assess the possibility that high or low doses of anxiolytics/hypnotics received by schizophrenic subjects affect their mismatch negativity (MMN), using event-related potentials (ERPs) and magnetoencephalography (MEG).


METHODS
Twenty-three and 16 patients with schizophrenia participated in the ERP and MEG studies, respectively. Three types of MMN (MMN in response to a duration change of pure-tone stimuli, within-category vowel change (Japanese vowel /a/ with short versus long duration), and across-category vowel change (vowel /a/ versus /o/)) were recorded.


RESULTS
High or low doses of benzodiazepine had no significant effects on MMN amplitude/magnetic MMN power, topography/laterality, or latency under any conditions of the ERP or MEG study.


CONCLUSIONS
These results suggest that chronic administration of anxiolytics/hypnotics does not significantly affect MMN in schizophrenia.
Kasai
Kiyoto
K
Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. kasaik@bwh.harvard.edu
Yamada
Haruyasu
H
Kamio
Satoru
S
Nakagome
Kazuyuki
K
Iwanami
Akira
A
Fukuda
Masato
M
Yumoto
Masato
M
Itoh
Kenji
K
Koshida
Ichiro
I
Abe
Osamu
O
Kato
Nobumasa
N
D000161:Acoustic Stimulation; D000328:Adult; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001288:Attention / Q000187:drug effects / Q000502:physiology*; D001569:Benzodiazepines; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects*; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D015225:Magnetoencephalography / Q000187:drug effects*; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects; D012559:Schizophrenia / Q000188:drug therapy* / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D014151:Anti-Anxiety Agents; D006993:Hypnotics and Sedatives; D001569:Benzodiazepines; D005680:gamma-Aminobutyric Acid