throughout the day are more likely to respond positively to sleep deprivation than individuals who show mood fluctuations that deviate from the typical pattern. one caveat to these findings is that a single individual may show diurnal fluctuations that vary day-to-day, showing typical diurnal changes on one day while not showing any changes (constant mood) on the next. this complexity was addressed in studies that followed single individuals and administered repeated sleep deprivation on days when the individual showed different mood fluctuations. the studies showed that an individual's ability to show the typical mood fluctuations was a better predictor of whether they would respond to sleep deprivation treatment than the individual's mood state on the particular day that they underwent sleep deprivation. short rem latency responsiveness to sleep deprivation is also currently believed to be dependent on observable pattern in a person's regular sleep cycle, such as how quickly a person enters into a sleep cycle called rapid eye movement (rem) sleep. individuals with depression typically show abnormally short rem sleep onsets, meaning they enter into the rem sleep stage earlier in the course of the night than matched healthy controls. individuals with depression who have short-latency rem sleep typically respond to sleep deprivation therapy more often than individuals with depression who do not show the typical short latency rem sleep pattern.