Nicotinic Receptor Density in Smoking and Nonsmoking Schizophrenics

Objective: The objective of this study is to determine the distribution and volume of distribution (Vt) in vivo of Beta2\* acetylcholine receptors (Beta2\* nAChR) in schizophrenic smokers and nonsmokers and compare this to published data from normal healthy subjects who are smokers and nonsmokers. Study population: Participants will be volunteers with a diagnosis of schizophrenia aged 18 to 50 years. The proposed sample size is 10 per group: nonsmokers or ex-smokers and smokers for a total of 20 participants. Design: One PET study lasting up to 8 hours after combination of bolus and continuous infusion administration of 2\[(18)F\] FA-85380. Smokers will be abstinent for at least 48 hrs. Subjects will also undergo a structural MRI scan for purposes of registration of PET scan data. Outcome Measures: Data from 20 schizophrenic patients (10 smokers and 10 nonsmokers) will be compared to published data from healthy controls. Total volume of distribution (VT) which is a measure of receptor density and distribution of Beta2 nAChR\* will be determined in Schizophrenic smokers and nonsmokers and differences in these values will be compared to published values for the differences in nicotinic acetylcholine receptor density in healthy smokers and nonsmokers (Mukhin et al., 2008) Also, receptor distribution and VT will be correlated with levels of smoking and symptom profiles in the schizophrenic patients studied.