oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

This is a syndrome where the patient has multiple cognitive deficits and memory loss sufficient to impair occupational or social functioning.

There is either:

  • Associated deterioration in language, perception and comprehension.
  • Impaired ability to recognise objects (agnosia).
  • And/or a disturbance in executive functioning (inability to think abstractly and plan, initiate, sequence, monitor and stop complex behaviour).

Deterioration must represent a progressive decline from a previous higher level of functioning, and consciousness should not be clouded (compare with acute confusional state or delirium).

Memory loss is typically for recent events and long-term memory can be remarkably intact.

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There are an estimated 163,000 new cases of dementia identified each year in England and Wales.[1] It increases with age:

  • 6.7 per 1,000 person years at age 65-69.
  • 68.5 per 1,000 person years at age 85 and above.[1]


It is very rare below 55 years. There is 3% prevalence by 70 years and it doubles every 5.1 years thereafter.

According to UK figures provided by the Alzheimer's Society, there were 683,597 patients with dementia in the UK (2006),[3] and this was expected to reach 940,110 by 2021.[3]

The society estimates the prevalence of late-onset dementia as 1.3% aged 65-69, 2.9% aged 70-74, 5.9% aged 75-79, 12.2% aged 80-84, 20.3% aged 85-89, 28.6% aged 90-94 and 32.5% aged 95+.[3]

Causes of adult onset dementia
NB: this is not an exhaustive list and mixed pathologies are common - 33.8%.[4][5]
Primary degenerations
Inherited metabolic and storage disorders
Infections and inflammation
Metabolic, toxic, etc.

Multi-infarct dementia is much less common nowadays. This is almost certainly because practices are diagnosing hypertension and treating it energetically at an early stage.

There are subtle differences in the presentation of different types of dementia. These are covered in detail in their specific articles.

In contrast to acute confusional state, which is usually of recent onset and may have a reversible cause, the history should go back at least several months and usually several years.

Consider dementia with Lewy bodies (DLB) in elderly patients presenting with hallucinations, lucid periods, movement disorders, falls or syncope. Making this diagnosis will have important implications for treatment (use of neuroleptics in these patients causes 2- to 3-fold excess mortality).[6]

For objective evidence, carry out a test of cognitive functioning (see 'Diagnosis', below).

The diagnosis of dementia should only be made after:

  • Comprehensive history and physical examination. The key to diagnosis is a good history of progressive impairment of memory and other cognitive functioning (usually requiring the help of a spouse, relative or friend).

    Make specific notes on the following:[7]
    • Attention and concentration ability.
    • Orientation - time, place, person.
    • Memory - both short- and long-term.
    • Praxis - whether they can get dressed, lay a table, etc.
    • Language function (usually evident during questioning).
    • Executive function - problem-solving, etc.
  • Conduct a formal screen for cognitive impairment - see separate article Screening for Cognitive Impairment.
  • Other reversible organic causes have been excluded.

Note: it is important to identify depression and treat it appropriately. Sometimes it is difficult to distinguish between depression and dementia and depression is quite common in dementia. If in doubt, treat.

  • Ensure no treatable cause has been missed, by arranging FBC, ESR or CRP, MSU, U&E, LFT, glucose, Ca2+, TFT, B12 and folate (red cell folate). Don't always believe low-normal B12s: cellular deficiency may co-exist - if in doubt ,one should treat (homocysteine metabolites may be a better test).[9]
  • Consider blood cultures, CXR and CT/MRI scan, and psychometric testing as appropriate to confirm diagnosis.
  • VDRL/TPHA should not be performed routinely - only if risk factors are present.
  • CSF examination should be used if Creutzfeldt-Jakob disease or other forms of rapidly progressive dementia are suspected.[10]
  • Patients with mild cognitive impairment (MCI) should be referred to memory assessment clinics. MCI is defined as a decline in cognitive function greater than expected, taking account of the subject's age and education, which is not interfering with activities of daily living (ADL).
  • Genetic clinical genotype analysis should only be requested where an inherited cause is suspected.[7]

Priorities for implementation:

  • Patients with dementia should not be discriminated against when considering treatment options for other conditions.
  • Their valid consent should be sought for treatment, wherever possible. This may mean making information available to them in an appropriate form. The use by patients and carers of advocacy services and voluntary organisations should be encouraged. If patients are not competent to make a decision, the requirements of the Mental Capacity Act 2005 should be followed.
  • Carers should receive an assessment of needs as required by the Carers and Disabled Children Act 2004 and the Carers (Equal Opportunities) Act 2004. Carers should be offered individual or group psycho-education and psychological therapy, peer-support groups, information in a variety of media, and training courses. Issues such as transport, night-sitting, and respite care should also be considered.
  • Health and social care managers should take a joint approach to management, and this should include joint written policies and procedures, and joint planning of services which take on board the views of local service users and carers.
  • Care managers and co-ordinators should ensure that a combined care plan, which takes account of the changing needs of the patient and the carers, is reviewed regularly, and receives the endorsement of the patient and carers.
  • Named health and/or social care staff should be assigned to operate the plan.
  • A memory assessment service should act as the single point of referral for all patients with a suspected diagnosis of dementia.

This means tailoring services to the individual needs of the person as far as possible.

Mental capacity to make decisions

If the patient does not have capacity to make decisions, the Department of Health guidance should all be followed.[11] Whilst the patient is in a relatively early stage of the condition, opportunity should be taken to discuss such issues as advanced statements (which outline how they would like decisions taken on their behalf, should they lose capacity), advance decisions about refusing treatment, Power of Attorney, and preferred place of care. The Mental Capacity Act 2005 has the following principles:

  • Adults must be assumed to have capacity to make decisions about their care unless proved otherwise.
  • Individuals should be given all available support to help them come to a decision.
  • Individuals should retain the right to make what others might consider eccentric or unwise decisions.
  • Anything done on behalf of an individual without capacity must be in that person's best interests.
  • The rights and basic freedoms of an individual without capacity should be restricted as little as possible.
  • With the patient's consent, relatives and carers should be involved in management decisions. Relatives and carers should also have their own needs assessed.

Diversity and equality

This section in the National Institute for Health and Clinical Excellence (NICE) guidance is a reminder about the importance of respecting individuality:
'Patients and carers should be given support appropriate to their needs and should not be discriminated against in terms of race, language, religion or sexuality. Focused support should be available for younger people with dementia, and for those with learning disabilities.'

Social, sexual and financial support

The effects of the condition on existing personal and sexual relationships should be discussed and patients and carers given information about local support services if appropriate. Information should be provided about financial issues, including direct payments, individual budgets, and possible eligibility for NHS continuing care.

Promoting independence

A care plan should be instituted that addresses activities of daily living (ADL), and considers such issues as the person's environment, toileting skills, and physical exercise.

For people who also have learning disability, consider using the Assessment of Motor and Process Skills (AMPS) at the time of diagnosis.[12] The Dementia Questionnaire for Mentally Retarded Persons (DMR) and Dalton's Brief Praxis Test (BPT) may be used for monitoring change in function.

Improving cognitive skills

People with mild-to-moderate dementia may improve if they participate in a structured group stimulation programme.

Community and hospital care

Patients should be cared for in the community as much as possible. However, if they become severely disturbed and need to be contained for their own safety or the safety of others, inpatient care should be considered (this might include those liable to be detained under the Mental Health Act 1983). Inpatient admission would also be justified for patients with complex physical and psychiatric problems who could not be properly assessed in the community.

Palliative and end-of-life care

Physical, psychological, social and spiritual support should be offered, and dementia patients should have the same access to palliative care services as any other patient. Oral nutrition should be encouraged for as long as possible. Percutaneous endoscopic gastrostomy (PEG) feeding may be appropriate in patients with transient dysphagia but is not recommended in patients with severe dementia, as there is no evidence of increased survival or reduced complications.[13][14][15] Decisions to withhold nutritional support should be taken within a legal and ethical framework.[16] Fever may be managed with antipyretics and mechanical cooling. Palliative antibiotics should be given after an individual assessment of the patient. Resuscitation is unlikely to succeed in patients with severe dementia. If no advanced decision has been taken by the patient, the decision to resuscitate should take into account the views of the carers and the multidisciplinary team, the Resuscitation Council UK 's guidance, and the Mental Capacity Act 2005.[17] The decisions should be recorded in the notes and care plan.

Acetylcholinesterase (AChE) inhibitors

NICE has recently reviewed its guidance on the use of these drugs (donepezil, galantamine or rivastigmine) in mild and moderate Alzheimer's disease,[18] bringing it in line with the Scottish Intercollegiate Guidelines Network (SIGN).[10]

  • Drug treatment should be considered in patients with mild or moderate Alzheimer's disease. It should only be started by dementia specialists (psychiatrists, neurologists, and physicians specialising in the care of older people), after appropriate discussion with family and carers. These drugs have cholinergic side-effects and should be started at a low dose, and then be titrated according to response.
  • It should be continued only as long as it is having a worthwhile effect on cognitive, global, functional or behavioural symptoms.
  • Patients on treatment should be reviewed regularly by an appropriate specialist team, or by shared care with GPs where such an agreement exists. This should include cognitive, global, functional and behavioural assessments and discussion with carers.

Whereas previous guidance concentrated on the mini-mental state examination (MMSE) score in discriminating between mild (21-26), moderate (15-19), moderately severe (10-14) and severe (<10) Alzheimer's disease when deciding to treat with AChE inhibitors, the new NICE guidelines now emphasise that the MMSE is just one measure to take into account when deciding to initiate or continue treatment.

N-methyl-D-aspartate (NMDA) antagonists

Memantine is an NMDA antagonist. It is recommended by NICE as an option for managing patients with moderate Alzheimer's disease where AChE inhibitors are not tolerated or are contra-indicated, or in the treatment of severe Alzheimer's disease.

  • Several short-term trials show efficacy of risperidone and olanzapine in reducing the rate of aggression, agitation, and psychosis.
  • Alternative treatments include anticonvulsants, such as valproate and carbamazepine, and short-acting benzodiazepines, such as lorazepam and oxazepam.[19]
  • The cholinergic deficits can contribute to the development of behavioural symptoms, and treatment with AChE inhibitors also shows improvements in behavioural symptoms.

Patients and relatives with a suspected genetic cause for dementia should be offered genetic counselling by the regional genetic services.

The focus for prevention should be the modification of behaviour in middle-aged and older people (reducing smoking, alcohol consumption, and obesity, and treating other cerebrovascular disease risk factors such as hypertension and hypercholesterolaemia).[7]

The outlook for most types of dementia is poor. Irreversible or untreated dementia usually continues to worsen over time. The condition usually progresses over years until the person's death.

Further reading & references

  1. Matthews F, Brayne C; The incidence of dementia in England and Wales: findings from the five identical sites of the MRC CFA Study. PLoS Med. 2005 Aug;2(8):e193. Epub 2005 Aug 23.
  2. Alzheimer's Society; Dementia care and research
  3. Alzheimer's Society; Alzheimer's Society Dementia UK: The Full Report, 2007
  4. Dementia in: Brain's diseases of the Nervous system; 10e OMP (1993) p755-62
  5. Holmes C, Cairns N, Lantos P, et al; Validity of current clinical criteria for Alzheimer's disease, vascular dementia and dementia with Lewy bodies. Br J Psychiatry. 1999 Jan;174:45-50.
  6. McKeith IG, Galasko D, Kosaka K, et al; Consensus guidelines for the clinical and pathologic diagnosis of dementia with Lewy bodies (DLB): report of the consortium on DLB international workshop. Neurology. 1996 Nov;47(5):1113-24.
  7. Dementia: Supporting people with dementia and their carers in health and social care; NICE Clinical Guideline (2006)
  8. Copeland JR; Assessment of dementia. Lancet. 1998 Mar 14;351(9105):769-70.
  9. Savage DG, Lindenbaum J, Stabler SP, et al; Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies. Am J Med. 1994 Mar;96(3):239-46.
  10. Management of patients with dementia, Scottish Intercollegiate Guidelines Network - SIGN (Feb 2006)
  11. Reference guide to consent for examination or treatment (second edition); Dept of Health
  12. Assessment of Motor and Process Skills, AMPS Project International (2007)
  13. Sampson EL, Candy B, Jones L; Enteral tube feeding for older people with advanced dementia. Cochrane Database Syst Rev. 2009 Apr 15;(2):CD007209.
  14. Kurien M, McAlindon ME, Westaby D, et al; Percutaneous endoscopic gastrostomy (PEG) feeding. BMJ. 2010 May 7;340:c2414. doi: 10.1136/bmj.c2414.
  15. Westaby D, Young A, O'Toole P, et al; The provision of a percutaneously placed enteral tube feeding service. British Society of Gastroenterology Guideline, published in Gut. 2010 Dec;59(12):1592-605.
  16. Nutritional Advice in Common Clinical Situations - Good Practice Guide; British Geriatrics Society (revised August 2009)
  17. Decisions Relating to Cardiopulmonary Resuscitation, A Joint Statement from the British Medical Association, the Resuscitation Council (UK) and the Royal College of Nursing, 2007
  18. Alzheimer's disease - donepezil, galantamine, rivastigmine and memantine; NICE Technology Appraisal Guideline (March 2011)
  19. Blennow K, de Leon MJ, Zetterberg H; Alzheimer's disease. Lancet. 2006 Jul 29;368(9533):387-403.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Huw Thomas
Current Version:
Peer Reviewer:
Dr John Cox
Last Checked:
Document ID:
2034 (v28)