Nicotine effects on mismatch negativity in nonsmoking schizophrenic patients.
BACKGROUND
The goal of the present study is to identify the effect of nicotine on auditory automatic processing, as reflected by mismatch negativity (MMN), in nonsmoking schizophrenic patients.


METHODS
Ten nonsmoking schizophrenic patients and 10 healthy volunteers underwent a reference session and 2 test sessions. The test sessions involved administration of a placebo patch and a nicotine skin patch, which were counterbalanced. Nicotine was administered transdermally under controlled dosage.


RESULTS
Nicotine administration shortened the MMN latencies (at Fz on nicotine/placebo: 134.8 +/- 5.7/157.6 +/- 6.4 ms) in healthy volunteers. In contrast, there were no significant differences in MMN latencies in schizophrenic patients (169.6 +/- 5.7/165.0 +/- 6.4 ms).


CONCLUSIONS
Nicotine activates and accelerates preattentive and automatic processing in healthy controls, whereas there were no such effects observed in nonsmoking patients. The impaired MMN response to nicotine administration in nonsmoking schizophrenic patients may be attributed to low nicotinic receptor function, implicated in dysregulation of the glutamatergic system.
Department of Psychiatry, Juntendo University School of Medicine, Koshigaya, Japan.
Rie
R
Inami
Eiji
E
Kirino
Reiichi
R
Inoue
Toshihito
T
Suzuki
Heii
H
Arai
D000161:Acoustic Stimulation / Q000379:methods; D000279:Administration, Cutaneous; D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D016022:Case-Control Studies; D003265:Contingent Negative Variation / Q000187:drug effects*; D004311:Double-Blind Method; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D009538:Nicotine / Q000008:administration & dosage*; D018722:Nicotinic Agonists / Q000008:administration & dosage*; D011930:Reaction Time / Q000187:drug effects; D012559:Schizophrenia / Q000503:physiopathology*; D013997:Time Factors
D018722:Nicotinic Agonists; D009538:Nicotine