Unconsciousness
Encyclopedia
Unconsciousness is the condition of being not conscious—in a mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli. Being in a comatose state or coma
is a type of unconsciousness. Fainting due to a drop in blood pressure and a decrease of the oxygen supply to the brain is a temporary loss of consciousness. Loss of consciousness must not be confused with altered states of consciousness, such as delirium
(when the person is confused and only partially responsive to the environment), normal sleep
, hypnosis
, and other altered states in which the person responds to stimuli.
Loss of consciousness should not be confused with the notion of the psychoanalytic unconscious
or cognitive processes (e.g., implicit cognition) that take place outside of awareness.
Loss of consciousness may occur as the result of traumatic brain injury
, brain hypoxia
(e.g., due to a brain infarction
or cardiac arrest), severe poisoning with drugs that depress the activity of the central nervous system (e.g., alcohol and other hypnotic or sedative drugs), severe fatigue, and other causes.
There is a theory that unconsciousness occurs when different regions of the brain inhibit one another.
, unconsciousness may entitle the criminal defendant to the defense
of automatism
, an excusing condition
that allows a defendant to argue that they should not be held criminally liable
for their actions or omissions. In most countries, courts must consider whether unconsciousness in a situation can be accepted as a defense; it can vary from case to case. Hence epileptic seizures, neurological
dysfunctions and sleepwalking
may be considered acceptable excusing conditions because the loss of control is not foreseeable, but falling asleep (especially while driving or during any other safety-critical activity), may not be because natural sleep rarely overcomes an ordinary person without warning.
In many countries, it is presumed that someone who is less than fully conscious cannot give consent
to anything. This can be relevant in cases of sexual behavior, euthanasia
or patients giving informed consent
with regard to starting or stopping a treatment.
Laws in some countries require that first responders, EMT, or paramedics obtain consent from an injured person who is conscious before they initiate patient care. In most situations where the injured person is deemed unconscious, consent is implied and the emergency service provider is free to provide care.
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
is a type of unconsciousness. Fainting due to a drop in blood pressure and a decrease of the oxygen supply to the brain is a temporary loss of consciousness. Loss of consciousness must not be confused with altered states of consciousness, such as delirium
Delirium
Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
(when the person is confused and only partially responsive to the environment), normal sleep
Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...
, hypnosis
Hypnosis
Hypnosis is "a trance state characterized by extreme suggestibility, relaxation and heightened imagination."It is a mental state or imaginative role-enactment . It is usually induced by a procedure known as a hypnotic induction, which is commonly composed of a long series of preliminary...
, and other altered states in which the person responds to stimuli.
Loss of consciousness should not be confused with the notion of the psychoanalytic unconscious
Unconscious mind
The unconscious mind is a term coined by the 18th century German romantic philosopher Friedrich Schelling and later introduced into English by the poet and essayist Samuel Taylor Coleridge...
or cognitive processes (e.g., implicit cognition) that take place outside of awareness.
Loss of consciousness may occur as the result of traumatic brain injury
Traumatic brain injury
Traumatic brain injury , also known as intracranial injury, occurs when an external force traumatically injures the brain. TBI can be classified based on severity, mechanism , or other features...
, brain hypoxia
Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...
(e.g., due to a brain infarction
Infarction
In medicine, infarction refers to tissue death that is caused by a local lack of oxygen due to obstruction of the tissue's blood supply. The resulting lesion is referred to as an infarct.-Causes:...
or cardiac arrest), severe poisoning with drugs that depress the activity of the central nervous system (e.g., alcohol and other hypnotic or sedative drugs), severe fatigue, and other causes.
There is a theory that unconsciousness occurs when different regions of the brain inhibit one another.
Law and medicine
In jurisprudenceJurisprudence
Jurisprudence is the theory and philosophy of law. Scholars of jurisprudence, or legal theorists , hope to obtain a deeper understanding of the nature of law, of legal reasoning, legal systems and of legal institutions...
, unconsciousness may entitle the criminal defendant to the defense
Defense (legal)
In civil proceedings and criminal prosecutions under the common law, a defendant may raise a defense in an attempt to avoid criminal or civil liability...
of automatism
Automatism (law)
-Definition:Automatism is a rarely used criminal defence. It is one of the mental condition defences that relate to the mental state of the defendant. Automatism can be seen variously as lack of voluntariness, lack of culpability or excuse...
, an excusing condition
Excuse
In jurisprudence, an excuse or justification is a defense to criminal charges that is distinct from an exculpation. In this context, "to excuse" means to grant or obtain an exemption for a group of persons sharing a common characteristic from a potential liability. "To justify" as in justifiable...
that allows a defendant to argue that they should not be held criminally liable
Legal liability
Legal liability is the legal bound obligation to pay debts.* In law a person is said to be legally liable when they are financially and legally responsible for something. Legal liability concerns both civil law and criminal law. See Strict liability. Under English law, with the passing of the Theft...
for their actions or omissions. In most countries, courts must consider whether unconsciousness in a situation can be accepted as a defense; it can vary from case to case. Hence epileptic seizures, neurological
Neurology
Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...
dysfunctions and sleepwalking
Sleepwalking
Sleepwalking, also known as somnambulism, is a sleep disorder belonging to the parasomnia family. Sleepwalkers arise from the slow wave sleep stage in a state of low consciousness and perform activities that are usually performed during a state of full consciousness...
may be considered acceptable excusing conditions because the loss of control is not foreseeable, but falling asleep (especially while driving or during any other safety-critical activity), may not be because natural sleep rarely overcomes an ordinary person without warning.
In many countries, it is presumed that someone who is less than fully conscious cannot give consent
Consent
Consent refers to the provision of approval or agreement, particularly and especially after thoughtful consideration.- Types of consent :*Implied consent is a controversial form of consent which is not expressly granted by a person, but rather inferred from a person's actions and the facts and...
to anything. This can be relevant in cases of sexual behavior, euthanasia
Euthanasia
Euthanasia refers to the practice of intentionally ending a life in order to relieve pain and suffering....
or patients giving informed consent
Informed consent
Informed consent is a phrase often used in law to indicate that the consent a person gives meets certain minimum standards. As a literal matter, in the absence of fraud, it is redundant. An informed consent can be said to have been given based upon a clear appreciation and understanding of the...
with regard to starting or stopping a treatment.
Laws in some countries require that first responders, EMT, or paramedics obtain consent from an injured person who is conscious before they initiate patient care. In most situations where the injured person is deemed unconscious, consent is implied and the emergency service provider is free to provide care.
See also
- Fainting
- ComaComaIn medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
- greyout, loss of color vision
- Traumatic brain injuryTraumatic brain injuryTraumatic brain injury , also known as intracranial injury, occurs when an external force traumatically injures the brain. TBI can be classified based on severity, mechanism , or other features...
- ConsciousnessConsciousnessConsciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...
- SyncopeSyncope (medicine)Syncope , the medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone characterized by rapid onset, short duration, and spontaneous recovery due to global cerebral hypoperfusion that most often results from hypotension.Many forms of syncope are...
- SleepSleepSleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...
- HypnosisHypnosisHypnosis is "a trance state characterized by extreme suggestibility, relaxation and heightened imagination."It is a mental state or imaginative role-enactment . It is usually induced by a procedure known as a hypnotic induction, which is commonly composed of a long series of preliminary...
- Do Not ResuscitateDo not resuscitateIn medicine, a "do not resuscitate" or "DNR" is a legal order written either in the hospital or on a legal form to respect the wishes of a patient to not undergo CPR or advanced cardiac life support if their heart were to stop or they were to stop breathing...
- Living willLiving willAn advance health care directive, also known as living will, personal directive, advance directive, or advance decision, are instructions given by individuals specifying what actions should be taken for their health in the event that they are no longer able to make decisions due to illness or...
- Shallow water blackoutShallow water blackoutA shallow water blackout is a loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive in water typically shallower than five metres , when the swimmer does not necessarily experience an urgent need to breathe and has no other obvious medical condition that might have...
- SomnophiliaSomnophiliaSomnophilia is a paraphilia in which sexual arousal or orgasm are stimulated by intruding on and awakening a sleeping person with erotic caresses, but not with force or violence...
- Soul Sleep