title: Differences in P50 and prepulse inhibition of the startle reflex between male smokers and non-smokers with first episode schizophrenia without medical treatment.
abstract: BACKGROUND
  Nicotine may improve schizophrenia patient's cognitive deficit symptoms. This study was to explore the chronic effects of smoking on prepulse inhibition of the startle reflex (PPI) and P50 in the patients with first-episode schizophrenia (FES).
  
  
  METHODS
  The event-related potentials (ERP) recording and analysis instrument made by Brain Products, Germany, was used to detect PPI and P50 in 49 male FES patients (FES group, n = 21 for smokers and n = 28 for non-smokers) and 43 normal male controls (control group, n = 19 for smokers and n = 24 for non-smokers).
  
  
  RESULTS
  Compared with normal controls, the FES group had prolonged PPI latency when elicited by single stronger stimulus (P < 0.05); the FES group had prolonged PPI latency and increased PPI amplitude (P < 0.05, 0.01) when elicited by weak and strong stimuli. The FES group had lower PPI inhibition rate than normal controls (P < 0.05). Compared with normal controls, the FES group had increased P50-S2 amplitude and increased amplitude ratio S2/S1 (both P <0.05). In the control group, the smokers had a tendency of increase in P50-S2 amplitude (P > 0.05) and shorter P50-S2 latency (P < 0.05) than the non-smokers. The smokers had higher PPI amplitude than the non-smokers (P < 0.05). In the FES group, the smokers had higher P50-S1 amplitude, shorter P50-S2 latency, and higher amplitude ratio S2/S1 than the non-smokers (P < 0.05, 0.01). The smokers had higher PPI amplitude than the non-smokers (P < 0.05).
  
  
  CONCLUSIONS
  There is obvious PPI and P50 deficits in schizophrenic patients. However, these deficits are relatively preserved in the smokers compared with the non-smokers, which suggests that long-term smoking might partially improve the sensory gating in schizophrenic patients. Whether this conclusion can be deduced to female patients requires further follow-ups.
authors.affiliation: Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Lisheng
authors.initials: L
authors.lastname: Song
authors.affiliation: Department of Electrophysiology, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China. Emal: chenxingshi2008@163.com.
authors.forename: Xingshi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Psychiatry, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Meijuan
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Medical Psychology, Faculty of Psychology and Mental Health, Second Military Medical University of PLA, Shanghai 200433, China. Email: tangyunxiang1973@tom.com.
authors.forename: Yunxiang
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of EEG Source Imaging, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Jijun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Electrophysiology, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Mingdao
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Electrophysiology, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Feiying
authors.initials: F
authors.lastname: Lou
authors.affiliation: Department of Electrophysiology, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Electrophysiology, Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Chong
authors.initials: C
authors.lastname: Chen
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005071:Evoked Potentials / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D013216:Reflex, Startle / Q000502:physiology*; D012559:Schizophrenia / Q000503:physiopathology*; D012907:Smoking / Q000009:adverse effects*; D055815:Young Adult