Re: There is no evidence base for proposed dementia screening
I congratulate the authors for writing an open letter on this crucial topic and generating a healthy debate.
I presume none of us can deny from the elephantine burden of dementia in the population as we age. This will only continue to grow given the increasing life expectancy.
In projected figures,By 2025, the number of people age 65 and older with Alzheimer’s disease is estimated to reach 6.7 million
— a 30 percent increase from the 5.2 million aged 65 and older currently affected. These figures can only begin to hint at the behavioural,affective issues and impaired quality of life faced on an individual level by a patient and immense care-giver's burden and exhaustion on the part of the primary care giver.
I agree with the authors that currently there is no evidence base for "screening" of dementia . Also, internationally screening is usually done when "treatment of diseases at their earlier stages should be more effective than treatment begun after the development of symptoms" for which we lack evidence when it comes to Dementia. However I still think that early detection for dementia will help us employ non-pharmacological measures as well as let the patient make important life decisions while the capacity remains and cherish memories. I agree with the authors on this note that here is no supporting data on pharmacological therapy for prevention, althought donepezil has some controversial efficacy in Mild Cognitive Impairment and first 12-month progression into Alzhiemer's. 
With the introduction of Mild Cognitive Impairment [nonamnestic type] in diagnostic manuals, hopefully this issue will be curtailed at an earlier point with 6 monthly visits for review/re-assesment but MCI itself needs more stringent criteria and diagnostic tool.
Many a times family members unconsiously tend to focus on affective and behavioural symptoms and not report memory problems unless probed into.The primary Issue hindering screening should not be internal fear of being labelled as Dementia on the part of patient. For this alone should not dictate our values/practices/forsightedness. It is also noteworthy to mention that the proposal of proactively asking for memory issues +/- screening tests is not for general population but age specific only [>75y].
To me, there is no harm in pro-actively asking for memory problems [if any] from all patients more than 75 years coming to a GP clinic and if needed, conducting a MMSE. What needs elaboration and debate is the extensivity and intensivity of screening tool /tests employed , need for revised guidelines and the prioritization in NHS fund allocation because without doubt, provision as without doubt, already diagnosed cases should top the list for fund allocation.
Also I believe that [especially in reference to dementia], research should not only narrow down to focusing on finding out objective evidence of slow progression of disease parameters if detected early but also on overall quality of life, satisfaction level, ease of acceptance of diagnosis and necessary delegation of responsibilities while insight/memory is relatively intact.
 Alzheimer’s Association, 2012 Alzheimer’s Disease Facts and Figures, Alzheimer’s & Dementia, Volume 8, Issue 2http://www.alz.org/downloads/facts_figures_2012.pdf
Deborah Blacker, editorial: Mild Cognitive Impairment — No Benefit from Vitamin E, Little from Donepezil. N Engl J Med 2005; 352:2439-2441http://www.nejm.org/doi/full/10.1056/NEJMe058086
Petersen RC. Mild cognitive impairment. N Engl J Med 2011;364:2227-2234