Sleep deprivation is the partial or near partial act of depriving the needed amount of R.E.M. sleep to an individual or organism.

Physiological effects

Generally, lack of sleep may result in

• aching muscles
• hallucinations
• hand tremors
• irritability
• memory lapses or loss
• severe yawning
• temper tantrums in children
• symptoms similar to:
• Attention-deficit Hyperactivity Disorder

Diabetes

A 1996 study by the University of Chicago Medical Center showed that sleep deprivation severely affects the human body's ability to metabolize glucose, which can lead to early-stage Diabetes Type 2.

Effects on the brain

Sleep deprivation can adversely affect brain function. A 2000 study, by the UCSD School of Medicine and the Veterans Affairs Healthcare System in San Diego, used functional magnetic resonance imaging technology to monitor activity in the brains of sleep-deprived subjects performing simple verbal learning tasks. The study showed that regions of the brain's prefrontal cortex displayed more activity in sleepier subjects. Depending on the task at hand, the brain would sometimes attempt to compensate for the adverse effects caused by lack of sleep. The temporal lobe, which is a brain region involved in language processing, was activated during verbal learning in rested subjects but not in sleep deprived subjects. The parietal lobe, not activated in rested subjects during the verbal exercise, was more active when the subjects were deprived of sleep. Although memory performance was less efficient with sleep deprivation, greater activity in the parietal region was associated with better memory.

A 2001 study at Chicago Medical Institute suggested that sleep deprivation may be linked to more serious diseases, such as heart disease and mental illnesses, such as psychosis and bipolar disorder.Fact: date=June 2008 A 2003 Universtity of California study found that REM sleep deprivation alleviates clinical depression. Although the mechanism is unclear it is suggested that the deprivation mimics the effects of selective serotonin reuptake inhibitors (SSRI). However, the study also indicated that REM sleep was essential for blocking neurotransmitters and allowing the neurotransmitter receptors to "rest" and regain sensitivity which in turn leads to improved regulation of mood and increased learning ability. Non REM sleep may allow enzymes to repair brain cell damage caused by free radicals. High metabolic activity while awake damages the enzymes themselves preventing efficient repair. The study observed the first evidence of brain damage in rats as a direct result of sleep deprivation.