<P> Sleep deprivation can adversely affect the brain and cognitive function . A 2000 study, by the University of California, San Diego School of Medicine and the Veterans Affairs Healthcare System in San Diego, used functional magnetic resonance imaging (fMRI) 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, an area that supports mental faculties such as working memory and logical and practical ("means - ends") reasoning, displayed more activity in sleepier subjects . Researchers interpreted this result as indicating that the brain of the average sleep - deprived subject had to work harder than that of the average non-sleep - deprived subject to accomplish a given task . They therefore concluded that the brains of sleep - deprived subjects were attempting to compensate for adverse effects caused by sleep deprivation . </P> <P> The temporal lobe, 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 . Getting less than the required number of hours needed to function leads to a decline in memory and judgement, this change in brain chemicals often leads to depression . Although memory performance was less efficient with sleep deprivation, greater activity in the parietal region was associated with better short term memory . </P> <P> A 2001 study at the Chicago Medical Institute suggested that sleep deprivation may be linked to serious diseases, such as heart disease and mental illness including psychosis and bipolar disorder . The link between sleep deprivation and psychosis was further documented in 2007 through a study at Harvard Medical School and the University of California at Berkeley . The study revealed, using MRI scans, that sleep deprivation causes the brain to become incapable of putting an emotional event into the proper perspective and incapable of making a controlled, suitable response to the event . </P> <P> The negative effects of sleep deprivation on alertness and cognitive performance suggest decreases in brain activity and function, primarily in the thalamus, a structure involved in alertness and attention, and in 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 h 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 . </P>

Can you get psychosis from lack of sleep