Objectives—To discover what dementia sufferers feel is wrong with them; what they have been told and by whom, and what they wish to know about their illness.Background—Ethical guidelines regarding telling truth appear to be equivocal. Declarations of cognitively intact subjects, attitudes of family members and current psychiatric practice all vary, but no previous research has been published concerning what patients with dementia would in fact like to know about their diagnosis and prognosis.Design—Questionnaire study of the patients' opinions.Setting—Old Age Psychiatry Service (...) in Worcester.Participants—30 consecutive patients with dementia.Results—The quality of information received has been poor and many patients have no opportunity to discuss their illness with anybody. Despite that almost half of the participants in this study had adequate insight and a majority declared that they would like to know more about their predicament.Conclusions—Although many patients would like to know the truth, the rights of those who do not want to know should also be respected. Therefore the diagnosis of dementia should not be routinely disclosed but health care professionals should seek to understand their patients' preferences and act appropriately according to their choice. (shrink)