Prepulse inhibition deficits in schizophrenia are modified by smoking status
Received 13 January 2009; received in revised form 7 April 2009; accepted 9 April 2009. published online 08 May 2009.
Abstract
Background
Schizophrenia is associated with high rates of cigarette smoking and deficits in sensorimotor gating, as measured by prepulse inhibition (PPI) of the startle response. However, the relationship between PPI deficits and smoking status is unclear. We examined whether smoking status modifies PPI deficits in schizophrenia.
Methods
We studied PPI as a function of smoking status and schizophrenia diagnosis in four groups using a cross-sectional design: Smokers with schizophrenia (SS; n=14), non-smokers with schizophrenia (SNS; n=15), control smokers (CS; n=11), and control non-smokers (CNS; n=10). PPI in smokers was recorded under conditions of smoking satiation, and smoking status was verified biochemically.
Results
The Diagnosis×Smoking Status×Prepulse Interval interaction was significant (F11,140=5.01, p<0.001). At all prepulse to pulse intervals (PPTPIs; 30, 60 and 120 ms), we found that SNS had reductions (~50%; p<0.01) in PPI compared to CNS. However, when SS were compared to CS under conditions of smoking satiation, SS had comparable levels of PPI to CS, and significantly higher levels of PPI than SNS.
Conclusions
Our findings suggest that PPI deficits are present in nonsmokers with schizophrenia, and may be modified by smoking status. Acute smoking in schizophrenia is associated with an elevation of PPI to the levels in non-psychiatric control smokers. These findings have significant implications for understanding vulnerability to tobacco dependence in schizophrenia, which may lead to the development of more effective treatments for PPI deficits and tobacco dependence in this population.
aDepartment of Psychiatry, University of Toronto, Toronto, Ontario, Canada M5T 1R8
bCentre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada M5T 1R8
cProgram for Research in Smokers with Mental Illness (PRISM), Department of Psychiatry, Yale School of Medicine, Department of Psychiatry, New Haven, Connecticut 06519, USA
Corresponding author. University of Toronto, Faculty of Medicine, 250 College Street, Room CS 734, Toronto, Ontario, Canada M5T 1R8. Tel.: +1 416 535 8501x4544; fax: +1 416 979 4676.
ABSTRACT