It may be tempting to seek solace in slumber after a traumatic event, but a study from the October 2012 issue of Neuropsychopharmacology found that sleeping too soon after trauma might lead to increased post-traumatic stress disorder symptoms. Two groups of rodents were exposed to a predator's scent, a traumatic event for a mouse. For six hours afterward, one group was prevented from sleeping, whereas a control group was not. The sleep-deprivation group displayed fewer physiological markers of stress than the control group and less PTSD-like behavior, such as freezing and a heightened startle response.

Researchers believe that sleep deprivation disrupts the consolidation of trauma memories—a hypothesis that jibes with the current understanding of the role of sleep in strengthening emotional memories. (Once that memory is ingrained, however, sleep could provide an opportunity for treatment; see the story at the right.)

Sleep deprivation can also reduce the impact of traumatic brain injury (TBI), according to a study published in the November 2012 issue of Neuroscience Letters. Rats with TBI sustained less damage when they were kept awake for 24 hours after the injury. Taken together, these findings suggest that after a violent, traumatic event—such as a car accident—staying awake for a while could afford both physical and mental protection.