A new animal model study developed by Prof. Hagit Cohen, Director of the Stress and Anxiety Research Unit in BGU’s Faculty of Health Sciences, in collaboration with Prof. Joseph Zohar of Tel Aviv University, has found that sleep deprivation after exposure to a traumatic event may prevent or reduce the risk of post trauma. Withholding sleep from rats in the first hours after exposure to a significantly stressful threat clearly shows that, just as sleep improves learning and memory consolidation, sleep deprivation interferes with the consolidation of traumatic memories and reduces the risk of post-traumatic stress disorder (PTSD).
Approximately 20% of people exposed to a severe traumatic event (for example, a car or work accident, terrorist attack or war) are unable to carry on their lives normally. Such people retain the memory of the event for many years, continually besieged by thoughts connected to the event, and display extreme anxiety and distress. These people are categorized as suffering from post-traumatic stress disorder - PTSD. It causes considerable difficulties in the patient's functioning in daily life and, in extreme cases, may render the patient completely dysfunctional
Often those close to someone exposed to a traumatic event, including medical teams, are keen to relieve the distress and assume that it would be best if they could rest and “sleep on it”. Studies have shown that animals and humans demonstrate increase memory consolidation and improved learning when allowed to sleep soon after being exposed to an event. "Since memory is a significant component in the development of post-traumatic symptoms, we decided to examine the various effects of sleep deprivation immediately after exposure to trauma" says Cohen.
Her team tested various aspects of responses to stress in controlled animal study models which studied PTSD in rats. "As is the case for human populations exposed to severe stress, 15-20% of the animals develop long-term disruptions in their behavior," says Cohen. "Our research method for this study is, we believe, a breakthrough in biomedical research."
Shlomo Cohen, a Psychology student working under Cohen, demonstrated in a series of experiments that sleep deprivation of six hours immediately after exposure to a traumatic event reduces the development of post-trauma like behavioral responses. Rats that underwent sleep deprivation after exposure to trauma did not remember it, while a control group of rats that was allowed to sleep after the stress exposure did remember, as shown by their post trauma-like behavior.
The animal model clearly shows that post traumatic behavioral symptoms are resoundingly reduced by sleep-deprivation. A pilot study in humans is currently being planned. It may be far better to prevent sleep, or at least not to encourage or induce sleep, after stress exposure.
Post-Exposure Sleep Deprivation article.pdf
