It’s a fact – extreme sleep deprivation makes people grumpier8. Moreover, there’s growing evidence that inadequate sleep causes anger, anxiety and sadness. For example, researchers at the University of Pennsylvania conducted a study in which people were only allowed to sleep 4.5 hours per night for one week9. During the week, the subjects were given a number of performance tests and assessments of mood, feelings and emotion and were rated on scales of stress and calmness, happiness and unhappiness, mental exhaustion and sharpness. The subjects were also asked to list any significant problems or complaints they had.

The study found conclusively that people who get less than a full night’s sleep feel more stressed, angry, sad and more mentally exhausted. Overall scores for mood and vigor declined steadily over the test days. Further, when the subjects were allowed to get sufficient sleep, their mood scores improved significantly.

8 National Sleep Foundation web site; www.sleepfoundation.org
9 Dement, W.C.; The Promise of SLEEP; Dell Publishing 1999, Pg. 275