COMPUTED AXIAL BRAIN TOMOGRAMS IN LONG-TERM BENZODIAZEPINE USERS

Computed axial brain tomograms were recorded in four groups of subject s: (a) subjects who had never taken benzodiazepines (n = 25); (b) subj ects who had taken them in the past for less than a year (n = 9); (c) patients currently taking benzodiazepines (n = 30); and (d) patients w ho had taken benzodiazepines in the past for at least a year and who h ad been withdrawn from medication for at least 6 months (n = 17). Vent ricle-to-brain ratios and tissue absorption to X-rays were computed. N o overall differences were found between the main groups. However, a f ew brain regions differed in density between nonusers and heavy users, particularly those taking lorazepam.