Is subcortical vascular dementia a clinical entity for clinical drug trials?

Several therapeutic trials have been performed for vascular dementia, with drugs differing in type and mechanism of action. The results have been almo st invariably inconclusive. Given the current notion that there are differe nt subtypes of vascular dementia according to pathophysiological mechanisms , it is reasonable to suspect that one of the main causes of the disappoint ing results was that the study samples included patients not fitting with t he rationale of selective treatments. Testing this hypothesis is difficult because characterization of patients in relation to different subtypes of v ascular dementia is not available for most studies. However, attempts an on going to reclassify patients entered in some trials for post hoc subgroup a nalyses with some preliminary interesting results. We propose that (1) spec ific subtypes of vascular dementia should be the target in any single trial using a treatment with a proper rationale; and (2) subcortical vascular de mentia caused by small vessel disease leading to lacunar infarcts and subco rtical white matter changes, represents a clinically and radiologically wel l-defined entity to be considered for future trials designed specifically f or testing adequate drugs.