Dementia is a decline or loss of reasoning, memory, and other mental abilities (the cognitive functions such as judgment, thinking, behavior, and language). This decline eventually impairs the ability to carry out everyday activities such as driving; household chores; and even personal care such as bathing, dressing, and feeding (often called activities of daily living, or ADLs).
About 4 to 5 million people in the United States have some degree of dementia, and that number will increase over the next few decades with the aging of the population; the following percentages are estimates and all forms of dementia are considered in these estimates:
Dementia is a very serious condition that results in significant financial and human costs.
Many older people fear that they are developing dementia because they cannot find their glasses or remember someone's name.
Dementia has many different causes, some of which are difficult to tell apart. Many medical conditions can cause dementia symptoms, especially in older people.
The main irreversible causes of dementia are described here. These damage brain cells in both cortical and subcortical areas. Treatment focuses on slowing progress of the underlying condition and relieving symptoms.
Treatable (potentially reversible) conditions
The dementia in treatable conditions may be reversible or partially reversible, even if the underlying disease or damage is not. However, readers should note that if underlying brain damage is extensive or severe, these causes may be classified as irreversible by the individual's physician(s).
Symptoms of dementia vary considerably by the individual and the underlying cause of the dementia. Most people affected by dementia have some (but not all) of these symptoms. The symptoms may be very obvious, or they may be very subtle and go unrecognized for some time. The first sign of dementia is usually loss of short-term memory. The person repeats what he just said or forgets where she put an object just a few minutes ago. Other symptoms and signs are as follows:
The person may not be aware of these problems, especially the behavior problems. This is especially true in the later stages of dementia.
Depression in elderly people can cause dementia-like symptoms. About 40% of people with dementia are also depressed. Common symptoms of depression include depressed mood, loss of interest in activities once enjoyed, withdrawal from others, sleep disturbances, weight gain or loss, suicidal thoughts, feelings of worthlessness, and loss of ability to think clearly or concentrate.
People with irreversible or untreated dementia present a slow, gradual decline in mental functions and movements over several years. Total dependence and death, often from infection, are the last stages
A person affected with dementia may not be aware he or she has a problem. Most people with dementia are brought to medical attention by a caring relative or friend. Any of the following warrant a visit to the person's health care professional.
In some people, the signs and symptoms of dementia are easily recognized; in others, they can be very subtle. A careful and thorough evaluation is needed to identify their true cause.
An assessment of dementia symptoms should include a mental status evaluation. This evaluation uses various "pencil and paper," "talking," and physical tests to identify brain dysfunction. A more thorough type of testing, performed by a psychologist, is called neuropsychologic testing.
Lab tests may be used to identify or rule out possible causes of dementia.
In some cases, imaging studies of the brain may be necessary to detect conditions such as normal pressure hydrocephalus, brain tumor, or infarction or bleeding in the brain.
Although an individual with dementia should always be under medical care, family members handle much of the day-to-day care. Medical care should focus on optimizing the individual's health and quality of life while helping family members cope with the many challenges of caring for a loved one with dementia. Medical care depends on the underlying condition, but it most often consists of medications and nondrug treatments such as behavioral therapy.
However, early investigation into the cause of dementia symptoms is urged because, as mentioned in the Dementia Causes section above, there are some conditions that when adequately treated may either limit or reverse dementia (see Dementia Medical Treatment section below).
Many individuals with dementia in the early and intermediate stages are able to live independently.
Other affected individuals require closer supervision or more constant assistance.
For individuals who are able to remain at home or to retain some degree of independent living, maintaining a familiar and safe environment is important.
Individuals with dementia should remain physically, mentally, and socially active.
A balanced diet that includes low-fat protein foods and plenty of fruits and vegetables helps maintain a healthy weight and prevents malnutrition and constipation. An individual with dementia should not smoke, both for health and for safety reasons.
Treatment of dementia focuses on correcting all reversible factors and slowing irreversible factors. This can improve function significantly, even in people who have irreversible conditions such as Alzheimer's disease. Some of the important treatment strategies in dementia are described here.
Correcting drug doses and/or withdrawing misused drugs
Many seniors require ongoing medications for chronic conditions such as heart failure, high blood pressure, high cholesterol, diabetes, prostate enlargement, and many others.
Slowing progression of dementia
Dementia due to some conditions, such as Alzheimer's disease, can sometimes be slowed in the early-to-intermediate stages with medication. Many different types of medications have been or are being tried in dementia. The medications that have worked the best so far are the cholinesterase inhibitors.
Because depression is so common in people with dementia, treatment of depression can at least partially relieve symptoms.
Treating specific medical disorders
Treatable disorders revealed by the diagnostic evaluation should receive prompt attention.
Treating specific symptoms and complications
Some symptoms and complications of dementia can be relieved by medical treatment, even if no treatment exists for the underlying cause of the dementia.
Except for the cholinesterase inhibitors, the U.S. Food and Drug Administration (FDA) has not approved any drug specifically for dementia. The drugs listed here are some of the most frequently prescribed from each class.
All drugs cause side effects. In prescribing a drug, doctors weigh whether the benefits of the drug outweigh the side effects. Seniors are especially likely to experience drug side effects. People with dementia who are taking any of these drugs must be checked often to make sure that the side effects are tolerable.
No accepted surgical treatment can manage dementia. Surgery is reserved for specific conditions underlying dementia that might improve the condition, such as removal of a brain tumor or drainage of excess cerebrospinal fluid.
Dementia Other Therapy
Occupational therapy may help persons with dementia with activities of daily living such as feeding oneself. Physical therapy may improve mobility by teaching patients to use canes or walkers properly and showing them how to get in and out of chairs or beds. Music and art activities may be soothing and rewarding for some people with dementia. Respite care, having a person with dementia go temporarily to a nursing home, is another important source of help for family caregivers.
After dementia has been diagnosed and treatment begun, the individual requires regular checkups with his or her health care professional.
No known way to prevent irreversible dementia or even many types of reversible dementia exists. The following may help prevent certain types of dementia:
The following may allow early treatment and at least partial reversal of dementia:
The outlook for most types of dementia is poor unless the cause is an early recognized reversible condition. Irreversible or untreated dementia usually continues to worsen over time. The condition usually progresses over years until the person's death.
Making decisions about end-of-life care is important.
Caring for a person with dementia can be very difficult. It affects every aspect of your life, including family relationships, work, financial status, social life, and physical and mental health. You may feel unable to cope with the demands of caring for a dependent, difficult relative. Besides the sadness of seeing the effects of your loved one's disease, you may feel frustrated, overwhelmed, resentful, and angry. These feelings may, in turn, leave you feeling guilty, ashamed, and anxious. Depression in caregivers is not uncommon.
Different caregivers have different thresholds for tolerating these challenges. For many caregivers, just "venting" or talking about the frustrations of caregiving can be enormously helpful. Others need more but may feel uneasy about asking for the help they need. one thing is certain, though: If the caregiver is given no relief, he or she can burn out, develop his or her own mental and physical problems, and become unable to care for the person with dementia.
This is why support groups were invented. Support groups are groups of people who have lived through the same set of difficult experiences and want to help themselves and others by sharing coping strategies. Mental health professionals strongly recommend that family caregivers take part in support groups. Support groups serve a number of different purposes for a person living with the extreme stress of being a caregiver for a person with dementia.
Support groups meet in person, on the telephone, or on the Internet. To find a support group that works for you, contact the organizations listed below. You can also ask your health care professional or behavioral therapist or go on the Internet. If you do not have access to the Internet, go to a public library. For more information about support groups, contact these agencies:
|Classification and external resources|
Dementia (taken from Latin, originally meaning "madness", from de- "without" + ment, the root of mens "mind") is a serious loss of global cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging. It may be static, the result of a unique global brain injury, or progressive, resulting in long-term decline due to damage or disease in the body. Although dementia is far more common in the geriatric population, it can occur before the age of 65, in which case it is termed "early onset dementia".
Dementia is not a single disease, but rather a non-specific illness syndrome (i.e., set of signs and symptoms) in which affected areas of cognition may be memory, attention, language, and problem solving. It is normally required to be present for at least 6 months to be diagnosed; cognitive dysfunction that has been seen only over shorter times, in particular less than weeks, must be termed delirium. In all types of general cognitive dysfunction, higher mental functions are affected first in the process.
Especially in the later stages of the condition, affected persons may be disoriented in time (not knowing what day of the week, day of the month, or even what year it is), in place (not knowing where they are), and in person (not knowing who they, or others around them, are). Dementia, though often treatable to some degree, is usually due to causes that are progressive and incurable as observed in primary progressive aphasia (PPA).
Symptoms of dementia can be classified as either reversible or irreversible, depending upon the etiology of the disease. Fewer than 10% of cases of dementia are due to causes that may presently be reversed with treatment. Causes include many different specific disease processes, in the same way that symptoms of organ dysfunction such as shortness of breath, jaundice, or pain are attributable to many etiologies.
Delirium can be easily confused with dementia due to similar symptoms. Delirium is characterized by a sudden onset, fluctuating course, a short duration (often lasting from hours to weeks), and is primarily related to a somatic (or medical) disturbance. In comparison, dementia has typically an insidious onset (except in the cases of a stroke or trauma), slow decline of mental functioning, as well as a longer duration (from months to years). Some mental illnesses, including depression and psychosis, may produce symptoms that must be differentiated from both delirium and dementia.
There are many specific types (causes) of dementia, often showing slightly different symptoms. However, the symptom overlap is such that it is impossible to diagnose the type of dementia by symptomatology alone, and in only a few cases are symptoms enough to give a high probability of some specific cause. Diagnosis is therefore aided by nuclear medicine brain scanning techniques. Certainty cannot be attained except with brain biopsy during life, or at autopsy in death.
Some of the most common forms of dementia are: Alzheimer's disease, vascular dementia, frontotemporal dementia, semantic dementia and dementia with Lewy bodies. It is possible for a patient to exhibit two or more dementing processes at the same time, as none of the known types of dementia protects against the others. Indeed, about ten per cent of people with dementia have what is known as "mixed dementia", which may be a combination of Alzheimer's disease and multi-infarct dementia.
Dementia is not merely a problem of memory. It reduces the ability to learn, reason, retain or recall past experience and there is also loss of patterns of thoughts, feelings and activities (Gelder et al. 2005). Additional mental and behavioral problems often affect people who have dementia, and may influence quality of life, caregivers, and the need for institutionalization. As dementia worsens individuals may neglect themselves and may become disinhibited and may become incontinent. (Gelder et al. 2005).
Depression affects 20–30% of people who have dementia, and about 20% have anxiety. Psychosis (often delusions of persecution) and agitation/aggression also often accompany dementia. Each of these needs to be assessed and treated independently of the underlying dementia.
In the United States, Florida's Baker Act allows law enforcement and the judiciary to force mental evaluation for those suspected of suffering from dementia or other mental incapacities.
In the United Kingdom, as with all mental disorders, where a person with dementia could potentially be a danger to themselves or others, they can be detained under the Mental Health Act 1983 for the purposes of assessment, care and treatment. This is a last resort, and usually avoided if the patient has family or friends who can ensure care.
The United Kingdom DVLA (Driving & Vehicle Licensing Agency) states that people with dementia who specifically suffer with poor short term memory, disorientation, lack of insight or judgment are almost certainly not fit to drive—and in these instances, the DVLA must be informed so said license can be revoked. They do however acknowledge low-severity cases and those with an early diagnosis, and those drivers may be permitted to drive pending medical reports.
Behaviour may be disorganized, restless or inappropriate. Some people become restless or wander about by day and sometimes at night. When people suffering from dementia are put in circumstances beyond their abilities, there may be a sudden change to tears or anger (a "catastrophic reaction").
David Cameron has described dementia as being a "national crisis", affecting 800,000 people in the United Kingdom. A competition by the Design Council found that the smell of a bakewell tart, wrist bands that could help and guide dogs for the mind[clarification needed] were all suggestions for ideas to help people with dementia. German nursing homes have installed fake bus stops so patients with dementia will "wait" for a bus there instead of wandering farther away.
Various types of brain injury, occurring as a single event, may cause irreversible but fixed cognitive impairment. Traumatic brain injury may cause generalized damage to the white matter of the brain (diffuse axonal injury), or more localized damage (as also may neurosurgery). A temporary reduction in the brain's supply of blood or oxygen may lead to hypoxic-ischemic injury. Strokes (ischemic stroke, or intracerebral, subarachnoid, subdural or extradural hemorrhage) or infections (meningitis and/or encephalitis) affecting the brain, prolonged epileptic seizures and acute hydrocephalus may also have long-term effects on cognition. Excessive alcohol use may cause alcohol dementia, Wernicke's encephalopathy and/or Korsakoff's psychosis, and certain other recreational drugs may cause substance-induced persisting dementia; once overuse ceases, the cognitive impairment is persistent but not progressive.
Dementia which begins gradually and worsens progressively over several years is usually caused by neurodegenerative disease; that is, by conditions affecting only or primarily the neurons of the brain and causing gradual but irreversible loss of function of these cells. Less commonly, a non-degenerative condition may have secondary effects on brain cells, which may or may not be reversible if the condition is treated.
The causes of dementia depend on the age at which symptoms begin. In the elderly population (usually defined in this context as over 65 years of age), a large majority of cases of dementia are caused by Alzheimer's disease, vascular dementia or both. Dementia with Lewy bodies is another fairly common cause, which again may occur alongside either or both of the other causes. Hypothyroidism sometimes causes slowly progressive cognitive impairment as the main symptom, and this may be fully reversible with treatment. Normal pressure hydrocephalus, though relatively rare, is important to recognize since treatment may prevent progression and improve other symptoms of the condition. However, significant cognitive improvement is unusual.
Dementia is much less common under 65 years of age. Alzheimer's disease is still the most frequent cause, but inherited forms of the disease account for a higher proportion of cases in this age group. Frontotemporal lobar degeneration and Huntington's disease account for most of the remaining cases. Vascular dementia also occurs, but this in turn may be due to underlying conditions (including antiphospholipid syndrome, CADASIL, MELAS, homocystinuria, moyamoya and Binswanger's disease). People who receive frequent head trauma, such as boxers or football players, are at risk of chronic traumatic encephalopathy (also called dementia pugilistica in boxers).
In young adults (up to 40 years of age) who were previously of normal intelligence, it is very rare to develop dementia without other features of neurological disease, or without features of disease elsewhere in the body. Most cases of progressive cognitive disturbance in this age group are caused by psychiatric illness, alcohol or other drugs, or metabolic disturbance. However, certain genetic disorders can cause true neurodegenerative dementia at this age. These include familial Alzheimer's disease, SCA17 (dominant inheritance); adrenoleukodystrophy (X-linked); Gaucher's disease type 3, metachromatic leukodystrophy, Niemann-Pick disease type C, pantothenate kinase-associated neurodegeneration, Tay-Sachs disease and Wilson's disease (all recessive). Wilson's disease is particularly important since cognition can improve with treatment.
At all ages, a substantial proportion of patients who complain of memory difficulty or other cognitive symptoms are suffering from depression rather than a neurodegenerative disease. Vitamin deficiencies and chronic infections may also occur at any age; they usually cause other symptoms before dementia occurs, but occasionally mimic degenerative dementia. These include deficiencies of vitamin B12, folate or niacin, and infective causes including cryptococcal meningitis, HIV, Lyme disease, progressive multifocal leukoencephalopathy, subacute sclerosing panencephalitis, syphilis and Whipple's disease.
Creutzfeldt-Jakob disease typically causes a dementia which worsens over weeks to months, being caused by prions. The common causes of slowly progressive dementia also sometimes present with rapid progression: Alzheimer's disease, dementia with Lewy bodies, frontotemporal lobar degeneration (including corticobasal degeneration and progressive supranuclear palsy).
On the other hand, encephalopathy or delirium may develop relatively slowly and resemble dementia. Possible causes include brain infection (viral encephalitis, subacute sclerosing panencephalitis, Whipple's disease) or inflammation (limbic encephalitis, Hashimoto's encephalopathy, cerebral vasculitis); tumors such as lymphoma or glioma; drug toxicity (e.g. anticonvulsant drugs); metabolic causes such as liver failure or kidney failure; and chronic subdural hematoma.
There are many other medical and neurological conditions in which dementia only occurs late in the illness, or as a minor feature. For example, a proportion of patients with Parkinson's disease develop dementia, though widely varying figures are quoted for this proportion. When dementia occurs in Parkinson's disease, the underlying cause may be dementia with Lewy bodies or Alzheimer's disease, or both. Cognitive impairment also occurs in the Parkinson-plus syndromes of progressive supranuclear palsy and corticobasal degeneration (and the same underlying pathology may cause the clinical syndromes of frontotemporal lobar degeneration). Chronic inflammatory conditions of the brain may affect cognition in the long term, including Behçet's disease, multiple sclerosis, sarcoidosis, Sjögren's syndrome and systemic lupus erythematosus. Although the acute porphyrias may cause episodes of confusion and psychiatric disturbance, dementia is a rare feature of these rare diseases.
Aside from those mentioned above, inherited conditions which may cause dementia alongside other features include:
Proper differential diagnosis between the types of dementia (cortical and subcortical) will require, at the least, referral to a specialist, e.g., a geriatric internist, geriatric psychiatrist, neurologist, neuropsychologist or geropsychologist. Duration of symptoms must evident for at least six months for a diagnosis of dementia or organic brain syndrome to be made (ICD-10).
There exist some brief tests (5–15 minutes) that have reasonable reliability and can be used in the office or other setting to screen cognitive status. Examples of such tests include the abbreviated mental test score (AMTS), the mini mental state examination (MMSE), Modified Mini-Mental State Examination (3MS), the Cognitive Abilities Screening Instrument (CASI), the Trail-making test, and the clock drawing test. Scores must be interpreted in the context of the person's educational and other background, and the particular circumstances; for example, a person highly depressed or in great pain will not be expected to do well on many tests of mental ability.
Another approach to screening for dementia is to ask an informant (relative or other supporter) to fill out a questionnaire about the person's everyday cognitive functioning. Informant questionnaires provide complementary information to brief cognitive tests. Probably the best known questionnaire of this sort is the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). on the other hand the General Practitioner Assessment Of Cognition combines both, a patient assessment and an informant interview. It was specifically designed for the use in the primary care setting and is also available as a web-based test.
Further evaluation includes retesting at another date, and administration of other tests of mental function.
Increasingly, clinical neuropsychologists provide diagnostic consultation following administration of a complex full battery of cognitive testing, often lasting several hours, to determine functional patterns of decline associated with varying types of dementia. Tests of memory, executive function, processing speed, attention, and language skills are relevant, as well as tests of emotional and psychological adjustment. These tests assist with ruling out other etiologies and determining relative cognitive decline over time or from estimates of prior cognitive abilities.
Routine blood tests are also usually performed to rule out treatable causes. These tests include vitamin B12, folic acid, thyroid-stimulating hormone (TSH), C-reactive protein, full blood count, electrolytes, calcium, renal function, and liver enzymes. Abnormalities may suggest vitamin deficiency, infection or other problems that commonly cause confusion or disorientation in the elderly. The problem is complicated by the fact that these cause confusion more often in persons who have early dementia, so that "reversal" of such problems may ultimately only be temporary.
Testing for alcohol and other known dementia-inducing drugs may be indicated.
A CT scan or magnetic resonance imaging (MRI scan) is commonly performed, although these modalities do not have optimal sensitivity for the diffuse metabolic changes associated with dementia in a patient that shows no gross neurological problems (such as paralysis or weakness) on neurological exam. CT or MRI may suggest normal pressure hydrocephalus, a potentially reversible cause of dementia, and can yield information relevant to other types of dementia, such as infarction (stroke) that would point at a vascular type of dementia.
The functional neuroimaging modalities of SPECT and PET are more useful in assessing long-standing cognitive dysfunction, since they have shown similar ability to diagnose dementia as a clinical exam. The ability of SPECT to differentiate the vascular cause from the Alzheimer's disease cause of dementias, appears to be superior to differentiation by clinical exam.
Recent research has established the value of PET imaging using carbon-11 Pittsburgh Compound B as a radiotracer (PIB-PET) in predictive diagnosis of various kinds of dementia, in particular Alzheimer's disease. Studies from Australia have found PIB-PET to be 86% accurate in predicting which patients with mild cognitive impairment would develop Alzheimer's disease within two years. In another study, carried out using 66 patients seen at the University of Michigan, PET studies using either PIB or another radiotracer, carbon-11 dihydrotetrabenazine (DTBZ), led to more accurate diagnosis for more than one-fourth of patients with mild cognitive impairment or mild dementia.
A study done at the University of Bari in Italy, found that a group drinking alcoholic beverages moderately had a slower progression to dementia. In a group of 1,566 elderly Italians, 1,445 had no cognitive impairment and 121 had suffered mild cognitive impairment, the study found that that over the duration of 3.5 years the people with MCI who drank less than one alcoholic beverage a day progressed to dementia at a rate that was 85% slower than those who drank no alcoholic beverages. However, the authors of the study commented that since it was epidemiologic, the findings might only be a marker of lifestyle, showing that "moderate lifestyle" in general is associated with slower dementia-progression. A study failed to show a conclusive link between high blood pressure and developing dementia. The study, published in the Lancet Neurology journal July 2008, found that blood pressure lowering medication did not reduce dementia but that meta analysis of the study data combined with other data suggested that further study could be warranted.
Except for the treatable types listed above, there is no cure to this illness. Cholinesterase inhibitors are often used early in the disease course. Cognitive and behavioral interventions may also be appropriate. Educating and providing emotional support to the caregiver (or carer) is of importance as well (see also elderly care).
It is important to recognize that since dementia impairs normal communication due to changes in receptive and expressive language, as well as the ability to plan and problem solve, agitated behaviour is often a form of communication for the person with dementia and actively searching for a potential cause, such as pain, physical illness, or overstimulation can be helpful in reducing agitation.  Additionally, using an “ABC analysis of behaviour” can be a useful tool for understanding behavior in patients with dementia. It involves looking at the antecedants (A), behavior (B), and consequences (C) associated with an event to help define the problem and prevent further incidents that may arise if the person’s needs are misunderstood. 
Currently, there are no medications that are clinically proven to be preventative or curative of dementia. Although some medications are approved for use in the treatment of dementia, these treat the behavioural and cognitive symptoms of dementia, but have no effect on the underlying pathophysiology.
"Off label" use of a drug is one that is a use that is not formally approved for the drug by the FDA, but is still legal at a doctor's discretion. Due to lack of formal FDA approval studies in the patient population to be treated, off label use of drugs is common in medical practice. In treating children, the mentally ill, and also persons with dementia, off label drug use is even more common, since lack of informed consent for the treatment group in studies makes these more expensive and difficult (since it must be done by proxy), so that for off-patent pharmaceuticals treatment studies are less often done, due to lack of funding.
Drugs sometimes used off-label to treat underlying causes of dementia, or symptoms of dementia, include:
As people age, they experience more health problems, and most health problems associated with aging carry a substantial burden of pain; so, between 25% and 50% of older adults experience persistent pain. Seniors with dementia experience the same prevalence of conditions likely to cause pain as seniors without dementia. Pain is often overlooked in older adults and, when screened for, often poorly assessed, especially among those with dementia since they become incapable of informing others that they're in pain. Beyond the issue of humane care, unrelieved pain has functional implications. Persistent pain can lead to decreased ambulation, depressed mood, sleep disturbances, impaired appetite and exacerbation of cognitive impairment, and pain-related interference with activity is a factor contributing to falls in the elderly.
Although persistent pain in the person with dementia is difficult to communicate, diagnose and treat, failure to address persistent pain has profound functional, psychosocial and quality of life implications for this vulnerable population. Health professionals often lack the skills and usually lack the time needed to recognize, accurately assess and adequately monitor pain in people with dementia. Family members and friends can make a valuable contribution to the care of a person with dementia by learning to recognize and assess their pain. Educational resources (such as the tutorial) and observational assessment tools are available.
Adult daycare centers as well as special care units in nursing homes often provide specialized care for dementia patients. Adult daycare centers offer supervision, recreation, meals, and limited health care to participants, as well as providing respite for caregivers.
In addition, Home care can provide one-on-one support and care in the home allowing for more individualized attention that is needed as the disease progresses.
Psychiatric nurses can make a distinctive contribution to people's mentalness. The four main premises upon which psychiatric nursing is based are:
The risks associated with the use of tubes are not well known. However, the risks include agitation and the patient pulling out the feeding tube, tubes becoming dislodged, clogged, or malpositioned. There is about a 1% fatality rate directly related to the procedure  with a 3% major complication rate 
Evidence from well-planned, representative epidemiological surveys is scarce in many regions, particularly in low-income countries. However, a 2009 study by Alzheimer Disease International estimated the global prevalence of dementia will almost double every 20 years, from 35.6 million in 2010, to 65.7 million by 2030 and 115.4 million by 2050. Around two thirds of individuals with dementia live in low and middle income countries, where the sharpest increases in numbers are predicted. A recent survey done by Harvard University School of Public Health and the Alzheimer's Europe consortium revealed that the second leading health concern (after cancer) among adults is Dementia.
Up to the end of the 19th century, dementia was a much broader clinical concept, which included mental illness and any type of psychosocial incapacity, including those which could be reversed. Dementia at this time simply referred to anyone who had lost the ability to reason, and was applied equally to psychosis of mental illness, "organic" diseases like syphilis which could destroy the brain, and to the dementia associated with old age, which was held to be caused by "hardening of the arteries."
Dementia when seen in the elderly was called senile dementia or senility and viewed as a normal and somewhat inevitable aspect of growing old, rather than as being caused by any specific diseases. At the same time, in 1907, a specific organic dementing process of early onset, called Alzheimer's disease, had been described. This was associated with particular microscopic changes in the brain, but was seen as a rare disease of middle age.
Much like other diseases associated with aging, dementia was rare before the 20th century, although by no means unknown, due to the fact that it is most prevalent in people over 80, and such lifespans were uncommon in preindustrial times. Conversely, syphilitic dementia was widespread in the developed world until largely being eradicated by the use of penicillin after WWII.
By the period of 1913-20, schizophrenia had been well-defined in a way similar to today, and also the term dementia praecox had been used to suggest the development of senile-type dementia at a younger age. Eventually the two terms fused, so that until 1952 physicians used the terms dementia praecox ("precocious dementia") and schizophrenia interchangeably. The term "precocious dementia" for a mental illness suggested that a type of mental illness like schizophrenia (including paranoia and decreased cognitive capacity) could be expected to arrive normally in all persons with greater age (see paraphrenia). At the same time, the beginning use of dementia to describe both what we now understand as schizophrenia and senile dementia, after about 1920, acted to give the word "dementia" a more limited role, as one of describing a type of permanent mental deterioration which was not expected to be reversible. This is the beginning of the more recognizable use of the term today.
In 1976, neurologist Robert Katzmann suggested a link between "senile dementia" and Alzheimer's disease. Katzmann suggested that much of the senile dementia occurring (by definition) after the age of 65, was pathologically identical with Alzheimer's disease occurring before age 65 and therefore should not be treated differently. He noted that the fact that "senile dementia" was not considered a disease, but rather part of aging, was keeping millions of aged patients experiencing what otherwise was identical with Alzheimer's disease from being diagnosed as having a disease process, rather than simply considered as aging normally. Katzmann thus suggested that Alzheimer's disease, if taken to occur over age 65, is actually common, not rare, and was the 4th or 5th leading cause of death, even though rarely being reported on death certificates in 1976.
This suggestion opened the view that dementia is never normal, and must always be the result of a particular disease process, and is not part of the normal healthy aging process, per se. The ensuing debate led for a time to the proposed disease diagnosis of "senile dementia of the Alzheimer's type" (SDAT) in persons over the age of 65, with "Alzheimer's disease" diagnosed in persons younger than 65 who had the same pathology. Eventually, however, it was agreed that the age limit was artificial, and that Alzheimer's disease was the appropriate term for persons with the particular brain pathology seen in this disease, regardless of the age of the person with the diagnosis. A helpful finding was that although the incidence of Alzheimer's disease increased with age (from 5-10% of 75-year-olds to as many as 40-50% of 90-year-olds), there was no age at which all persons developed it, so it was not an inevitable consequence of aging, no matter how great an age a person attained. Evidence of this is shown by numerous documented supercentenarians (people living to 110+) that experienced no serious cognitive impairment.
Also, after 1952, mental illnesses like schizophrenia were removed from the category of "organic brain syndromes," and thus (by definition) removed from possible causes of "dementing illnesses" (dementias). At the same, however, the traditional cause of senile dementia– "hardening of the arteries" – now returned as a set of dementias of vascular cause (small strokes). These were now termed "multi-infarct dementias" or vascular dementias.
In the 21st century, a number of other types of dementia have been differentiated from Alzheimer's disease and vascular dementias (these two being the most common types). This differentiation is on the basis of pathological examination of brain tissues, symptomatology, and by different patterns of brain metabolic activity in nuclear medical imaging tests such as SPECT and PETscans of the brain. The various forms of dementia have differing prognoses (expected outcome of illness), and also differing sets of epidemologic risk factors. The causal etiology of many of them, including Alzheimer's disease, remains unknown, although many theories exist such as accumulation of protein plaques as part of normal aging, inflammation, inadequate blood sugar, and traumatic brain injury.