However, in a subset of cases, sleep deprivation can paradoxically lead to increased energy and alertness and enhanced mood; although its long-term consequences have never been evaluated, sleep deprivation has even been used as a treatment for depression.Few studies have compared the effects of acute total sleep deprivation and chronic partial sleep restriction. A complete absence of sleep over a long period is not frequent in humans (unless they have fatal insomnia or specific issues caused by surgery); it appears that brief microsleeps cannot be avoided. Long-term total sleep deprivation has caused death in lab animals. Causes
Insomnia
Insomnia, one of the six types of dyssomnia, affects 21–37% of the adult population. Many of its symptoms are easily recognizable, including excessive daytime sleepiness; frustration or worry about sleep; problems with attention, concentration, or memory; extreme mood changes or irritability; lack of energy or motivation; poor performance at school or work; and tension headaches or stomach aches. Insomnia can be grouped into primary and secondary, or comorbid, insomnia.Primary insomnia is a sleep disorder not attributable to a medical, psychiatric, or environmental cause. There are three main types of primary insomnia. These include: psychophysiological, idiopathic insomnia, and sleep state misperception (paradoxical insomnia). Psychophysiological insomnia is anxiety-induced. Idiopathic insomnia generally begins in childhood and lasts the rest of a persons life. Its suggested that idiopathic insomnia is a neurochemical problem in a part of the brain that controls the sleep-wake cycle, resulting in either under-active sleep signals or over-active wake signals.
Effects and consequences
Brain
One study suggested, based on neuroimaging, that 35 hours of total sleep deprivation in healthy controls negatively affected the brains ability to put an emotional event into the proper perspective and make a controlled, suitable response to the event.The negative effects of sleep deprivation on alertness and cognitive performance suggest decreases in brain activity and function. These changes primarily occur in two regions: the thalamus, a structure involved in alertness and attention; and the prefrontal cortex, a region sub-serving alertness, attention, and higher-order cognitive processes. This was the finding of an American study in 2000. Seventeen men in their 20s were tested. Sleep deprivation was progressive with measurements of glucose (absolute regional CMRglu), cognitive performance, alertness, mood, and subjective experiences collected after 0, 24, 48, and 72 hours of sleep deprivation. Additional measures of alertness, cognitive performance, and mood were collected at fixed intervals. PET scans were used and attention was paid to the circadian rhythm of cognitive performance. Interestingly, the effects of sleep deprivation appear to be constant across "night owls" and "early birds", or different sleep chronotypes, as revealed by fMRI and graph theory.A noted 2002 University of California animal study indicated that non-rapid eye movement sleep (NREM) is necessary for turning off neurotransmitters and allowing their receptors to "rest" and regain sensitivity which allows monoamines (norepinephrine, serotonin and histamine) to be effective at naturally produced levels. This leads to improved regulation of mood and increased learning ability.