Health and Medicine

in human beings, the extent of an individual’s continuing physical, emotional, mental, and social ability to cope with his environment.

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  Ben Carson
  American politician and neurosurgeon who performed the first successful separation of conjoined twins who were attached at the back of the head (occipital craniopagus twins). The operation, which took place in 1987, lasted some 22 hours and involved a 70-member surgical team. Carson also refined a technique known as hemispherectomy, in which one-half...
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  tuberculosis (TB)
  TB infectious disease that is caused by the tubercle bacillus, Mycobacterium tuberculosis. In most forms of the disease, the bacillus spreads slowly and widely in the lungs, causing the formation of hard nodules (tubercles) or large cheeselike masses that break down the respiratory tissues and form cavities in the lungs. Blood vessels also can be eroded...
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  Lyme disease
  tick -borne bacterial disease that was first conclusively identified in 1975 and is named for the town in Connecticut, U.S., in which it was first observed. The disease has been identified in every region of the United States and in Europe, Asia, Africa, and Australia. Lyme disease is caused by several closely related spirochetes (corkscrew-shaped...
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  Sigmund Freud
  Austrian neurologist, founder of psychoanalysis. Freud’s article on psychoanalysis appeared in the 13th edition of the Encyclopædia Britannica. Freud may justly be called the most influential intellectual legislator of his age. His creation of psychoanalysis was at once a theory of the human psyche, a therapy for the relief of its ills, and an optic...
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  cancer
  group of more than 100 distinct diseases characterized by the uncontrolled growth of abnormal cells in the body. Though cancer has been known since antiquity, some of the most significant advances in scientists’ understanding of it have been made since the middle of the 20th century. Those advances led to major improvements in cancer treatment, mainly...
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  pneumonia
  inflammation and consolidation of the lung tissue as a result of infection, inhalation of foreign particles, or irradiation. Many organisms, including viruses and fungi, can cause pneumonia, but the most common causes are bacteria, in particular species of Streptococcus and Mycoplasma. Although viral pneumonia does occur, virus es more commonly play...
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  chronic traumatic encephalopathy (CTE)
  CTE degenerative brain disease typically associated with repetitive trauma to the head. Chronic traumatic encephalopathy (CTE) originally was known as dementia pugilistica, a term introduced in the 1920s and ’30s to describe mental and motor deficits associated with repeated head injury in boxers. Later scientists identified a set of cerebral changes...
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  Down syndrome
  congenital disorder caused by an extra chromosome on the chromosome 21 pair, giving the person a total of 47 chromosomes rather than the normal 46. British physician John Langdon Down first described the physical features of the disorder in 1866, and thus the disorder was later named for him. The physical and mental impacts of Down syndrome range from...
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  AIDS
  transmissible disease of the immune system caused by the human immunodeficiency virus (HIV). HIV is a lentivirus (literally meaning “slow virus”; a member of the retrovirus family) that slowly attacks and destroys the immune system, the body’s defense against infection, leaving an individual vulnerable to a variety of other infections and certain malignancies...
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  Alzheimer disease
  degenerative brain disorder that develops in mid-to-late adulthood. It results in a progressive and irreversible decline in memory and a deterioration of various other cognitive abilities. The disease is characterized by the destruction of nerve cells and neural connections in the cerebral cortex of the brain and by a significant loss of brain mass....
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  diabetes mellitus
  disorder of carbohydrate metabolism characterized by impaired ability of the body to produce or respond to insulin and thereby maintain proper levels of sugar (glucose) in the blood. Diabetes is a major cause of morbidity and mortality, though these outcomes are not due to the immediate effects of the disorder. They are instead related to the diseases...
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  autism
  developmental disorder affecting physical, social, and language skills, with an onset of signs and symptoms typically before age three. The term autism (from the Greek autos, meaning “self”) was coined in 1911 by Swiss psychiatrist Eugen Bleuler, who used it to describe withdrawal into one’s inner world, a phenomenon he observed in individuals with...
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  ophthalmology
  medical specialty dealing with the diagnosis and treatment of diseases and disorders of the eye. The first ophthalmologists were oculists. These paramedical specialists practiced on an itinerant basis during the Middle Ages. Georg Bartisch, a German physician who wrote on eye diseases in the 16th century, is sometimes credited with founding the medical...
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  syphilis
  systemic disease that is caused by the spirochete bacterium Treponema pallidum. Syphilis is usually a sexually transmitted disease, but it is occasionally acquired by direct nonsexual contact with an infected person, and it can also be acquired by an unborn fetus through infection in the mother. A related group of infections, collectively known as...
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  Crohn disease
  chronic inflammation of the digestive tract, usually occurring in the terminal portion of the ileum, the region of the small intestine farthest from the stomach. Crohn disease was first described in 1904 by Polish surgeon Antoni Leśniowski. It was later named for American gastroenterologist Burrill Bernard Crohn, who in 1932, in collaboration with...
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  IQ
  (from “intelligence quotient”), a number used to express the relative intelligence of a person. It is one of many intelligence tests. IQ was originally computed by taking the ratio of mental age to chronological (physical) age and multiplying by 100. Thus, if a 10-year-old child had a mental age of 12 (that is, performed on the test at the level of...
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  lobotomy
  surgical procedure in which the nerve pathways in a lobe or lobes of the brain are severed from those in other areas. The procedure formerly was used as a radical therapeutic measure to help grossly disturbed patients with schizophrenia, manic depression and mania (bipolar disorder), and other mental illnesses. Evidence that surgical manipulation of...
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  Alexander Graham Bell
  Scottish-born American inventor, scientist, and teacher of the deaf whose foremost accomplishments were the invention of the telephone (1876) and the refinement of the phonograph (1886). Alexander (“Graham” was not added until he was 11) was born to Alexander Melville Bell and Eliza Grace Symonds. His mother was almost deaf, and his father taught elocution...
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  dengue
  acute, infectious, mosquito-borne fever that is temporarily incapacitating but rarely fatal. Besides fever, the disease is characterized by an extreme pain in and stiffness of the joints (hence the name “breakbone fever”). Complication of dengue fever can give rise to a more severe form, called dengue hemorrhagic fever (DHF), which is characterized...
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  obesity
  excessive accumulation of body fat, usually caused by the consumption of more calories than the body can use. The excess calories are then stored as fat, or adipose tissue. Overweight, if moderate, is not necessarily obesity, particularly in muscular or large-boned individuals. Defining obesity Obesity was traditionally defined as an increase in body...
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  Asperger syndrome
  a neurobiological disorder characterized by autism -like abnormalities in social interactions but with normal intelligence and language acquisition. The disorder is named for Austrian physician Hans Asperger, who first described the symptoms in 1944 as belonging to a condition he called autistic psychopathy. Today, Asperger syndrome is considered an...
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  schizophrenia
  any of a group of severe mental disorders that have in common such symptoms as hallucinations, delusions, blunted emotions, disordered thinking, and a withdrawal from reality. Schizophrenics display a wide array of symptoms, but five main types of schizophrenia, differing in their specific symptomatology as follows, are recognized by some authorities....
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  homeopathy
  a system of therapeutics, notably popular in the 19th century, which was founded on the stated principle that “like cures like,” similia similibus curantur, and which prescribed for patients drugs or other treatments that would produce in healthy persons symptoms of the diseases being treated. This system of therapeutics based upon the “law of similars”...
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  nudism
  the practice of going without clothes, generally for reasons of health or comfort. Nudism is a social practice in which the sexes interact freely but commonly without engaging in sexual activities. The origin of the practice in Germany in the early 20th century coincided with a rebellion against the rigid moral attitudes of the late 19th century. The...
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  bipolar disorder
  mental disorder characterized by recurrent depression or mania with abrupt or gradual onsets and recoveries. There are several types of bipolar disorder, in which the states of mania and depression may alternate cyclically, one mood state may predominate over the other, or they may be mixed or combined with each other. Examples of types of the disorder,...
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  borderline personality disorder (BPD)
  BPD mental illness characterized by chronic instability in the affected individual’s mood, relationships, and sense of identity. The term borderline was first brought into psychiatric terminology in 1938 by American psychoanalyst Adolph Stern. Stern used it to describe patients who were “on the border” of psychosis and neurosis, individuals who displayed...
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  multiple sclerosis (MS)
  MS a progressive disease of the central nervous system characterized by the destruction of the myelin sheath surrounding the nerve fibres of the brain, spinal cord, and optic nerves. As a result, the transmission of nerve impulses becomes impaired, particularly in pathways involved with vision, sensation, and movement. Prevalence and types of multiple...
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  psychology
  scientific discipline that studies psychological and biological processes and behaviour in humans and other animals. The discipline of psychology is broadly divisible into two parts: a large profession of practitioners and a smaller but growing science of mind, brain, and social behaviour. The two have distinctive goals, training, and practices, but...
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  Parkinson disease
  a degenerative neurological disorder that is characterized by the onset of tremor, muscle rigidity, slowness in movement (bradykinesia), and stooped posture (postural instability). The disease was first described in 1817 by the British physician James Parkinson in his Essay on the Shaking Palsy. Parkinson disease is the primary form of parkinsonism,...
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  amyotrophic lateral sclerosis (ALS)
  ALS degenerative neurological disorder that causes muscle atrophy and paralysis. The disease usually occurs after age 40; it affects men more often than women. ALS is frequently called Lou Gehrig disease in memory of the famous baseball player Lou Gehrig, who died from the disease in 1941. Course of the disease ALS affects the motor neurons—i.e., those...