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| Unconsciousness | |
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| An unconscious male human lying in arecovery position | |
| Specialty | Psychiatry Neurology Cardiology Pulmonology Emergency medicine |
Unconsciousness is a state in which a livingindividual exhibits a complete, or near-complete, inability to maintainan awareness of self and environment or to respond to any human or environmentalstimulus.[1] Unconsciousness may occur as the result oftraumatic brain injury,brain hypoxia (inadequate oxygen, possibly due to a braininfarction orcardiac arrest), severe intoxication with drugs thatdepress the activity of the central nervous system (e.g.,alcohol and otherhypnotic orsedative drugs), severefatigue,pain,anaesthesia, and other causes.
Loss of consciousness should not be confused with the notion of thepsychoanalytic unconscious, cognitive processes that take place outside awareness (e.g.,implicit cognition), and withaltered states of consciousness such assleep,delirium,hypnosis, and other altered states in which the person responds to stimuli, includingtrance andpsychedelic experiences.
This is not a complete list.
Injurisprudence, unconsciousness may entitle thecriminal defendant to thedefense ofautomatism, i.e. a state without control of one's own actions, anexcusing condition that allows a defendant to argue that they should not be held criminallyliable for their actions oromissions. In most countries, courts must consider whether unconsciousness in a situation can be accepted as a defense; it can vary from case to case. Henceepileptic seizures,neurological dysfunctions, andsleepwalking 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, 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 giveconsent to anything. This can be relevant in cases ofsexual assault,euthanasia, or patients givinginformed consent with regard to starting or stopping a medical treatment.
