BRAIN IMAGINGEffects of frequent marijuana use on brain tissue volume and compositionBlock, Robert I.1,7; O'Leary, Daniel S.2; Ehrhardt, James C.3; Augustinack, Jean C.4,6; Ghoneim, M M.1; Arndt, Stephan2; Hall, James A.5Author Information 1Department of Anesthesia, Westlawn Building, Room 5140, Iowa City, IA 52242-1100 USA 2Department of Psychiatry, University of Iowa, Iowa City, IA 52242-1100 USA 3Department of Radiology, University of Iowa, Iowa City, IA 52242-1100 USA 4Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242-1100 USA 5School of Social Work, University of Iowa, Iowa City, IA 52242-1100 USA 6Present Address: Alzheimer's Research Unit, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA 02129, USA 7Corresponding Author: Robert I. Block Acknowledgements: This research was supported by grants DA10554, NIDA, NIH, and RR00059, General Clinical Research Centers Program, NCRR, NIH. Thanks to William Yuh, M.D. for providing clinical interpretations of each MRI; Linda Smith and Michael Daugherty for assisting in data collection; Karen Cretsinger and Helen Keefe for trimming the traces of the hippocampus; and C.K. Brown for statistical analyses. Received 10 November 1999; accepted 3 December 1999 NeuroReport: February 28, 2000 - Volume 11 - Issue 3 - p 491-496 Buy Abstract To investigate CNS effects of frequent marijuana use, brain tissue volume and composition were measured using magnetic resonance imaging (MRI) in 18 current, frequent, young adult marijuana users and 13 comparable, non-using controls. Automated image analysis techniques were used to measure global and regional brain volumes, including, for most regions, separate measures of gray and white matter. The marijuana users showed no evidence of cerebral atrophy or global or regional changes in tissue volumes. Volumes of ventricular CSF were not higher in marijuana users than controls, but were, in fact, lower. There were no clinically significant abnormalities in any subject's MRI. Sex differences were detected in several global volume measures. © 2000 Lippincott Williams & Wilkins, Inc.