The term is found again in Thomas Willis (1621–1675) influential De anima brutorum (1672), where lethargy (pathological sleep), coma (heavy sleeping), carus (deprivation of the senses) and apoplexy (into which carus could turn and which he localized in the white matter) are mentioned. The term carus is also derived from Greek, where it can be found in the roots of several words meaning soporific or sleepy. It can still be found in the root of the term carotid. Thomas Sydenham (1624–89) mentioned the term coma in several cases of fever (Sydenham, 1685). Signs and symptoms
General symptoms of a person in a comatose state are:

Inability to voluntarily open the eyes
A non-existent sleep-wake cycle
Lack of response to physical (painful) or verbal stimuli
Depressed brainstem reflexes, such as pupils not responding to light
Irregular breathing
Scores between 3 and 8 on the Glasgow Coma Scale

Causes
Many types of problems can cause a coma. Forty percent of comatose states result from drug poisoning. Certain drug use under certain conditions can damage or weaken the synaptic functioning in the ascending reticular activating system (ARAS) and keep the system from properly functioning to arouse the brain. Secondary effects of drugs, which include abnormal heart rate and blood pressure, as well as abnormal breathing and sweating, may also indirectly harm the functioning of the ARAS and lead to a coma. Given that drug poisoning is the cause for a large portion of patients in a coma, hospitals first test all comatose patients by observing pupil size and eye movement, through the vestibular-ocular reflex. (See Diagnosis below.
This trapping of matter in their lower respiratory tract can ultimately lead to infection, resulting in aspiration pneumonia.Coma patients may also deal with restlessness or seizures. As such, soft cloth restraints may be used to prevent them from pulling on tubes or dressings and side rails on the bed should be kept up to prevent patients from falling. Caregivers
Coma has a wide variety of emotional reactions from the family members of the affected patients, as well as the primary care givers taking care of the patients. Research has shown that the severity of injury causing coma was found to have no significant impact compared to how much time has passed since the injury occurred. Common reactions, such as desperation, anger, frustration, and denial are possible. The focus of the patient care should be on creating an amicable relationship with the family members or dependents of a comatose patient as well as creating a rapport with the medical staff. Although there is heavy importance of a primary care taker, secondary care takers can play a supporting role to temporarily relieve the primary care takers burden of tasks. Prognosis
Comas can last from several days to, in particularly extreme cases, years. Some patients eventually gradually come out of the coma, some progress to a vegetative state, and others die.