Impaired prepulse inhibition and habituation of acoustic startle response in Japanese patients with schizophrenia.
Prepulse inhibition (PPI) and habituation of the acoustic startle reflex (ASR) are considered to be candidate endophenotypes of schizophrenia. However, to our knowledge, only one group has investigated these startle measures in Asian patients with schizophrenia. In the present study, we evaluated these startle measures in 51 Japanese patients with schizophrenia and compared them with those of 55 healthy age- and sex-matched Japanese controls. A human startle response monitoring system was used to deliver acoustic startle stimuli, and record and score the electromyographic activity of the orbicularis oculi muscle. The startle measures examined were mean magnitude of ASR to pulse alone trials in initial block (SR), habituation of ASR during the session (HAB), and PPI at prepulse intensities of 82 dB (PPI82), 86 dB (PPI86), and 90 dB (PPI90) sound pressure level. SR was not significantly different between the patients and controls. Patients displayed significantly reduced HAB and PPI for all prepulse intensities compared to controls. The greatest statistical difference in PPI between patients and controls was found with PPI86. This did not correlate with any clinical variable in each group. Our results indicate that PPI and habituation of ASR are impaired in Asian patients with schizophrenia.
Takahashi
Hidetoshi
H
Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. hidetaka@psy.med.osaka-u.ac.jp
Iwase
Masao
M
Ishii
Ryouhei
R
Ohi
Kazutaka
K
Fukumoto
Motoyuki
M
Azechi
Michiyo
M
Ikezawa
Koji
K
Kurimoto
Ryu
R
Canuet
Leonides
L
Nakahachi
Takayuki
T
Iike
Naomi
N
Tagami
Shinji
S
Morihara
Takashi
T
Okochi
Masayasu
M
Tanaka
Toshihisa
T
Kazui
Hiroaki
H
Yoshida
Tetsuhiko
T
Tanimukai
Hitoshi
H
Yasuda
Yuka
Y
Kudo
Takashi
T
Hashimoto
Ryota
R
Takeda
Masatoshi
M
D000161:Acoustic Stimulation; D000328:Adult; D001767:Blinking / Q000187:drug effects; D003627:Data Interpretation, Statistical; D004576:Electromyography; D005260:Female; D006185:Habituation, Psychophysiologic / Q000187:drug effects*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D013216:Reflex, Startle / Q000187:drug effects*; D012565:Schizophrenic Psychology; D055815:Young Adult