Regional planimetric measurements of internal and external CSF spaces were performed in CT scans of 23 patients with endogenous depression (ICD 9, 296.1) and 28 patients with neurotic depression (ICD 9, 300.4) as compared to 56 control individuals without neuropsychiatric disorder. In female patients with endogenous depression, but not in men, the bilateral upper cortical sulci were widened, especially in the frontal regions, and the third ventricle was enlarged. In contrast, the female neurotic depressed group showed no enlargement of CSF spaces, but a narrowing of the Sylvian fissure and of the basal frontal lobe reaching level of significance in the right fronto-temporal region (P = 0.005). No narrowing of CSF spaces was observed in women with endogenous depression. A discriminant analysis of significantly changed CSF regions resulted in a correct classification in 82.4% of depressed women in either the endogenous or the neurotic group. Determination of divergent types of brain pathology might prove as a useful tool in validating the differential classification of these two main subtypes of affective disorders.