In 17 benzodiazepine (BDZ) dependent in-patients a CT scan was performed before initiation of withdrawal therapy. The evaluation of the ventricular to brain ratio (VBR) by standardized and computerized measurements revealed significantly higher mean VBRs for both high- and low-dose BDZ-dependent patients compared to the mean VBR of an age- and sex-matched control group. In addition, the mean VBR of high-dose BDZ-dependent patients (N = 8) was significantly higher than the mean VBR of low-dose BDZ-dependent patients (N = 9). This difference could not be accounted for by the age of the patients or duration of BDZ-dependency and, therefore, suggests a dose-dependent effect of BDZs on the enlargement of internal CSF-spaces. On the other hand, higher values for the width of external CSF-spaces were found to be related to increasing age of the patients and duration of BDZ-dependency.