I recently ran across a new study that illuminates the negative effects of sleep deprivation on emotional regulation (a link to it as at the bottom of this article). One of my first posts was on the importance of sleep to our emotional well-being. Basically, the sleep deprived brain is not able to regulate emotion. In the well-rested brain, the amygdala (a region of the brain that puts the body on alert so we can protect ourselves in times of danger) is functioning normally. However, in the sleep-deprived brain the amygdala gets stuck in overdrive, so to speak. Normally, when the brain perceives there is a threat, the amygdala becomes active but the prefrontal cortex, which is involved in our higher reasoning and logical thinking abilities, is able to step in and regulate the amygdala (and thus our emotions) when it turns out that a fight or flight response is not warranted.
Thus, a sleep-deprived person is likely to overreact to relatively minor irritations with more intense emotions than are warranted. As they state in the article “…while a good night’s rest can regulate your mood and help you cope with the next day’s emotional challenges, sleep deprivation does the opposite by excessively boosting the part of the brain most closely connected to depression, anxiety, and other psychiatric disorders.”
It’s likely that most mood problems such as depression and anxiety have a reciprocal-causal relationship with sleep deprivation. Thus, an anxious person is likely to lose some sleep and, as he/she becomes sleep-deprived, his/her anxious responses to stimuli are likely to increase. Then the person has even more difficulties sleeping because of the heightened anxiety and so on.
So, if you become sleep-deprived, for whatever reason, it’s likely to increase negative emotions such as depression, anger, and anxiety. Not that increased sleep is a total panacea, but it will only help your mood (and your cognitive functioning like memory) when you are able to get more sleep.
Here’s a link to the full article: http://www.berkeley.edu/news/media/releases/2007/10/22_sleeploss.shtml