title: Cigarette smoking and white matter microstructure in schizophrenia.
abstract: The majority of patients with schizophrenia smoke cigarettes. Both nicotine use and schizophrenia have been associated with alterations in brain white matter microstructure as measured by diffusion tensor imaging (DTI). The purpose of this study was to examine fractional anisotropy (FA) in smoking and non-smoking patients with schizophrenia and in healthy volunteers. A total of 43 patients (28 smoking and 15 non-smoking) with schizophrenia and 40 healthy, non-smoking participants underwent DTI. Mean FA was calculated in four global regions of interest (ROIs) (whole brain, cerebellum, brainstem, and total cortical) as well as in four regional ROIs (frontal, temporal, parietal and occipital lobes). The non-smoking patient group had a significantly higher intellectual quotient (IQ) compared with the patients who smoked, and our results varied according to whether IQ was included as a covariate. Without IQ correction, significant between-group effects for FA were found in four ROIs: total brain, total cortical, frontal lobe and the occipital lobe. In all cases the FA was lower among the smoking patient group, and highest in the control group. Smoking patients differed significantly from non-smoking patients in the frontal lobe ROI. However, these differences were no longer significant after IQ correction. FA differences between non-smoking patients and controls were not significant. Among smoking and non-smoking patients with schizophrenia but not healthy controls, FA was correlated with IQ. In conclusion, group effects of smoking on FA in schizophrenia might be mediated by IQ. Further, low FA in specific brain areas may be a neural marker for complex pathophysiology and risk for diverse problems such as schizophrenia, low IQ, and nicotine addiction.
authors.affiliation: Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN, USA. rega0026@umn.edu
authors.forename: Kathryn R
authors.initials: KR
authors.lastname: Cullen
authors.forename: Stuart
authors.initials: S
authors.lastname: Wallace
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Magnotta
authors.forename: Jeremy
authors.initials: J
authors.lastname: Bockholt
authors.forename: Stefan
authors.initials: S
authors.lastname: Ehrlich
authors.forename: Randy L
authors.initials: RL
authors.lastname: Gollub
authors.forename: Dara S
authors.initials: DS
authors.lastname: Manoach
authors.forename: Beng C
authors.initials: BC
authors.lastname: Ho
authors.forename: Vincent P
authors.initials: VP
authors.lastname: Clark
authors.forename: John
authors.initials: J
authors.lastname: Lauriello
authors.forename: Juan R
authors.initials: JR
authors.lastname: Bustillo
authors.forename: S Charles
authors.initials: SC
authors.lastname: Schulz
authors.forename: Nancy C
authors.initials: NC
authors.lastname: Andreasen
authors.forename: Vince D
authors.initials: VD
authors.lastname: Calhoun
authors.forename: Kelvin O
authors.initials: KO
authors.lastname: Lim
authors.forename: Tonya
authors.initials: T
authors.lastname: White
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D001933:Brain Stem / Q000473:pathology; D002531:Cerebellum / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D002552:Cerebral Ventricles / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007360:Intelligence / Q000502:physiology; D056784:Leukoencephalopathies / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D012016:Reference Values; D012559:Schizophrenia / Q000473:pathology*; D012907:Smoking / Q000009:adverse effects*; D013702:Temporal Lobe / Q000473:pathology; D014029:Tobacco Use Disorder / Q000473:pathology*