See L. L. Heston and J. White, The Vanishing Mind (1991).
Any of a group of severe mental disorders that have in common symptoms such as hallucinations, delusions, blunted emotions, disorganized thinking, and withdrawal from reality. Five main types are recognized: the paranoid, characterized by delusions of persecution or grandeur combined with unrealistic, illogical thinking and frequent auditory hallucinations; the disorganized (hebephrenic), characterized by disordered speech and behaviour and shallow or inappropriate emotional responses; the catatonic, characterized by motor inflexibility or stupor along with mutism, echolalia, or other speech abnormalities; the simple or undifferentiated type, which conforms to basic definitions of schizophrenia but does not exhibit particular behaviours in the aforementioned types; and the residual type, which is a chronic stage indicating advancement toward later-stage schizophrenia. Schizophrenia seems to occur in 0.5–1percnt of the general population, and more than half of those so diagnosed will eventually recover. There is strong evidence that genetic inheritance plays a role, but no single cause of schizophrenia has been identified. Stressful life experiences may help trigger its onset. Treatment consists of drug therapy and counseling.
Learn more about schizophrenia with a free trial on Britannica.com.
Chronic, usually progressive deterioration of intellectual functions. Most common in the elderly, it usually begins with short-term-memory loss once thought a normal result of aging but now known to result from Alzheimer disease. Other common causes are Pick disease and vascular disease. Dementia also occurs in Huntington chorea, paresis (see paralysis), and some types of encephalitis. Treatable causes include hypothyroidism (see thyroid gland), other metabolic diseases, and some malignant tumours. Treatment may arrest dementia's progress but usually does not reverse it.
Learn more about dementia with a free trial on Britannica.com.
Dementia (from Latin de- "apart, away" + mens (genitive mentis) "mind") is the progressive decline in cognitive function due to damage or disease in the body beyond what might be expected from normal aging. Although dementia is far more common in the geriatric population, it may occur in any stage of adulthood. This age cutoff is defining, as similar sets of symptoms due to organic brain dysfunction are given different names in populations younger than adulthood (see, for instance, developmental disorders).
Dementia is a non-specific illness syndrome (set of symptoms) in which affected areas of cognition may be memory, attention, language, and problem solving. 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, month, or even what year it is), in place (not knowing where they are), and in person (not knowing who they are).
Symptoms of dementia can be classified as either reversible or irreversible, depending upon the etiology of the disease. Less than 10 percent of cases of dementia are due to causes which 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. Without careful assessment of history, the short-term syndrome of delirium can easily be confused with dementia, because they have many symptoms in common. Some mental illnesses, including depression and psychosis, may also produce symptoms which must be differentiated from both delirium and dementia.
A copy of the MMSE can be found in the appendix of the original publication.
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).
Further evaluation includes retesting at another date, and administration of other (and sometimes more complex) tests of mental function, such as formal neuropsychological testing.
Chronic use of substances such as alcohol can also predispose the patient to cognitive changes suggestive of dementia.
Dementia and early onset dementia have been associated with neurovisceral porphyrias. Porphyria is listed in textbooks in the differential diagnosis of dementia. Because acute intermittent porphyria, hereditary coproporphyria and variegate porphyria are aggravated by environmental toxins and drugs the disorders should be ruled out when these etiologies are raised.
A Canadian study found that a lifetime of bilingualism has a marked influence on delaying the onset of dementia by an average of four years when compared to monolingual patients. The researchers determined that the onset of dementia symptoms in the monolingual group occurred at the mean age of 71.4, while the bilingual group was 75.5 years. The difference remained even after considering the possible effect of cultural differences, immigration, formal education, employment and even gender as influences in the results.
Tacrine (Cognex), donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon) are approved by the United States Food and Drug Administration (FDA) for treatment of dementia induced by Alzheimer disease. They may be useful for other similar diseases causing dementia such as Parkinsons or vascular dementia.
Haloperidol (Haldol), risperidone (Risperdal), olanzapine (Zyprexa), and quetiapine (Seroquel) are frequently prescribed to help manage psychosis and agitation. Treatment of dementia-associated psychosis or agitation is intended to decrease psychotic symptoms (for example, paranoia, delusions, hallucinations), screaming, combativeness, and/or violence.
Depression is frequently associated with dementia and generally worsens the degree of cognitive and behavioral impairment. Antidepressants may be helpful in alleviating cognitive and behavior symptoms by reuptaking neurotransmitter regulation through reuptake of serotonin, noradrenaline and dopamine.
Many patients with dementia experience anxiety symptoms. Although benzodiazepines like diazepam (Valium) have been used for treating anxiety in other situations, they are often avoided because they may increase agitation in persons with dementia or are too sedating. Buspirone (Buspar) is often initially tried for mild-to-moderate anxiety.
Selegiline, a drug used primarily in the treatment of Parkinson's disease, appears to slow the development of dementia. Selegiline is thought to act as an antioxidant, preventing free radical damage. However, it also acts as a stimulant, making it difficult to determine whether the delay in onset of dementia symptoms is due to protection from free radicals or to the general elevation of brain activity from the stimulant effect.
The main method to prevent dementia is to live an active life, both mentally and physically. It appears that the regular moderate consumption of alcohol (beer, wine, or distilled spirits) may reduce risk.
Furthermore, there are medications which might contribute to prevent the onset of dementia, including hypertension medications, anti-diabetic drugs, and NSAIDs. A study has shown a link between high blood pressure and developing dementia. The study, published in the Lancet Neurology journal July 2008, found that blood pressure lowering medication reduced dementia by 13%.
Studies published in US journals suggested that a Mediterranean diet or long-term beta-carotene supplements could ward off dementia.
Dementia Should Not Halt All Life's Simple Pleasures; AGENDA It Knows No Social or Class Barriers and Famous Names Who Have Fallen Victim Include Terry Pratchett, Ronald Reagan and Rita Hayworth. but Dementia Is Still Not Being Treated as Seriously as It Should, Says Berni Blackledge
Mar 15, 2008; Terry Pratchett's recent donation for research into dementia got me thinking. How might pounds 500,000 benefit my branch...