Dementia describes a chronic and progressive clinical syndrome characterised by cognitive impairment (particularly memory loss), inability to perform activities of daily living, and neuropsychiatric features (psychiatric symptoms and behavioural disturbances, also known as behavioural and psychological symptoms of dementia or BPSD). It affects an estimated 800 000 people in the UK and four million in the USA. Alzheimer’s disease (AD) is the most common cause of dementia (60%), followed by vascular dementia (VaD) (20%) (although 20% of people have both AD and VaD) and dementia with Lewy bodies (DLB) (15%). There have been significant advances in treatments available for dementia in the last few years.

CHOLINESTERASE INHIBITORS

Cholinesterase inhibitors (ChEIs) are the mainstay of treatment of Alzheimer’s disease. Randomised controlled trials (RCTs) have reported statistically significant, and clinically modest, effects of ChEIs. Trials have been short, conducted over six months, although effects have been reported, in open label extensions, to last up to five years. The primary aim of the trials has been to assess the treatment response for cognitive decline. This is most often measured using the Alzheimer’s disease assessment scale (ADAS-Cog),¹ which assesses multiple cognitive outcomes and is an accepted standard for measuring cognitive abilities in clinical trials. The total score of the ADAS-Cog ranges from 0–70, the higher score indicating greater impairment. Over a six month period untreated patients with mild to moderate AD typically deteriorate as signified by an increase of 3–4 points on the ADAS-Cog. Patients with moderate to severe AD have an increase of 4–6 points over the same period of time.² The Cochrane Review of donepezil for AD found an improvement at 24 weeks of 2.9 on the ADAS-Cog compared with placebo.³ Similar findings were reported in the Cochrane reviews of galantamine⁴ and rivastigmine.⁵ Another primary aim of trials has …