Inadequate sleep leads to many social and physical problems for the individual and for the society he or she lives in. Primary (and a source of many social problems) is a reduction in cognitive function and vigilance. Response time to stimuli slows, the size of the working memory appears to decrease, the ability to learn is compromised, and creative thinking becomes more difficult as the ability for divergent thinking deteriorates. Not only do jobs and tasks require quick reaction times (e.g. driving) see a downturn in performance, so do more subtle cerebral jobs involving judgement and creativity. We are not as smart as individuals when we are sleep deprived and society suffers, too.
Sleep loss interferes with all manner of daytime functioning.
People who have been deprived of sleep (ether partial deprivation or total deprivation) are susceptible to involuntary episodes of microsleep, and even when not experiencing microsleeps have less vigilance, give less attention to tasks requiring brainpower, and show an increased number of errors when tested on cognitive tasks.
People suffering from partial sleep deprivation suffer from poor mood and a decline in cognitive function http://www.ncbi.nlm.nih.gov/pubmed/9231952/
If you don’t get enough sleep you are more apt to catch a cold http://www.ncbi.nlm.nih.gov/pubmed/19139325/
And are more apt to become obese http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2082964/
In the long run, people with who run chronically low on sleep are more likely to get diabetes. http://www.ncbi.nlm.nih.gov/pubmed/16227462/
And increases the severity of metabolic disorders commonly associated with aging, e.g. metabolic disorder http://www.ncbi.nlm.nih.gov/pubmed/10543671/
Plus people suffering from inadequate sleep feel pain more acutely and perceive their general health as poorer than well rested people. http://www.ncbi.nlm.nih.gov/pubmed/8621064?dopt=Abstract
Chronic sleep restriction (not letting people sleep enough) over time leads to "cumulative, dose-dependent deterioration of attention and reaction time" Sometime people can do short, defined tasks well but performance deteriorates as tasks duration increases.
In controlled studies psychologists saw these declines in performance, and interestingly, the subjects seemed unaware of their handicap. They did not know they were having problems.
Drowsy driving is so bad we have a section of the Sleepdex website about it. Industrial accidents are more frequent when workers are tired. Drowsy driving accidents are often more serious than other wrecks because they often occur on high speed highways (because the driver is maintaining the same speed for a long period of time), there is no attempt to avoid the crash since the driver’s eyes are closed, and the driver is usually alone with no one to alert him or her. Long-haul truck drivers sometimes break the rules and sleep only two to four hours per night. Sleep deprivation has been shown to reduce the ability to make good split-second decisions that are needed in many jobs.
Shift workers are especially vulnerable to sleep deprivation. An alarming increase in the frequency of accidents happens during the graveyard shift. Notable incidents that have been due in part to sleep deprivation include the Exxon Valdez oil spill and Three Mile Island accident. Shift workers are also at particular risk for drowsy driving automobile accidents when driving home.
When workers have been sleep deprived their productivity drops and their risk for being party to an accident on the job increases. Fatigue and sleep deficit are known to increase the odds of a mishap. Most of the time these mishaps do not injure anyone, but some do.
A large-scale study in The Netherlands showed the connection. This study was notable for the integrity of its construction. Workers were selected to be followed by researchers before any accidents occurred, The workers’ sleep habits and patterns were examined. That way, there was no way a person involved with an accident could mis-report good or poor sleep before an accident.
The role of fatigue and drowsiness in workplace accidents is no secret. It’s known in industrial hygiene, safety, and human resources circles. And the workers often know they are at risk, The authors of a Swedish study on the topic found "self-reported disturbed sleep is a predictor of accidental death at work" The question is whether managers use this information responsibly,
A survey of workers in France showed 8% of those with insomnia had an industrial accident in the previous 12 months versus only 1% of good sleepers.
Other researchers estimate those with insomnia are 2.5 to 4.5 times more likely to have an accident than those without.
No, sleep deprivation does not make people mentally ill in any meaningful sense. Insomnia is a very common symptom of many mental illnesses, so confusion occasionally arises about cause and effect. But sleep researchers do not feel that sleep deprivation causes psychosis or schizophrenia or depression or similar problems.
"Visual misperceptions" happen to sleepy people, but these are not the same as hallucinations or waking dreams. Auditory hallucinations are not experienced by sleep deprived people.
Sleep deprivation is particularly a problem for children. In studies of elementary aged children, nearly 40% had some type of sleep problem, 15% exhibited bedtime resistance and 10% had daytime sleepiness. Nearly half of teens reported at least occasional difficulty in falling or staying asleep and almost 13% experiencing chronic and severe insomnia. This lack of sleep greatly affects mood, behavior, and academic performance. In pediatric research, poor sleepers reported being significantly more depressed and were even more likely to have a negative self-image. They were also more likely to exhibit type A behavior patterns and inferior coping behaviors and have more behavioral problems at home and in school. One study showed that students that students with C’s, D’s and F’s went to bed an average of 40 minutes later and got 20 minutes less sleep than A students. Insufficient sleep has also been associated with Attention Deficit Hyperactivity Disorder (ADHD), lower social skills and learning difficulties.
Are you and your family sleep-deprived? Sleep clinics measure sleep debt through use of a sleep latency test, which measures how easily someone can fall asleep. When this test is performed several times in a day it is called a multiple sleep latency test. However, there are ways to tell if you are sleep-deprived without going to a sleep clinic. Experts say that needing an alarm clock in order to wake up is a sign that you are sleep deprived. Another is falling asleep within five minutes of your head hitting the pillow unlike well-rested people who tend to nod off after 10 to 15 minutes. Napping easily is a third sign.
With children, it is important to remember that they will rarely complain of sleep problems. Also, parents are often unaware of how long it takes their children to fall asleep and how often they awake during the night. Therefore, it is important to talk with their children about how well they sleep and monitor them for signs of sleep deprivation. More
Law enforcement professionals sometimes employ forced sleep deprivation to get prisoners to talk – the idea being that tired people have lower resistance to truth telling. It's hard to lie when you're sleepy. The United Nations considers such tactics a form of torture.
This is one reason it is difficult to get data on the effects of sleep deprivation on humans and conclusions must be based on animal experiments or indirect observations. Ethical scientists cannot torture human subjects even if the subjects give their permission.
More nefarious techniques such as attempts to "brain wash" prisoners also employ sleep deprivation. More on this. .