The Behavioural Dysfunction Questionnaire discriminates behavioural variant frontotemporal dementia from Alzheimer's disease dementia and major depressive disorder.

BDQ-scores without any time criterion discriminated highly between early-stage bvFTD and non-bvFTD groups, which could improve the early diagnosis of bvFTD. With its standardised procedure, the BDQ is also appropriate for repeated assessments.