Sleep or No Sleep after a Trauma?
By Jim Windell
As a society, we’ve become more aware of the fact that Posttraumatic Stress Disorder (PTSD) is a symptom of exposure to trauma. Many veterans of the nearly-20-year war we’ve waged in Afghanistan have returned home suffering from PTSD. But, because of the pandemic, first responders are especially vulnerable to the trauma of round-the-clock treatment of covid 19 victims. Additionally, there are significant groups in our society who are routinely exposed to trauma because of accidents, natural disasters, violence, and abuse.
Having greater sensitivity to the plight of those exposed to trauma, that is, however, only the first step. Treating and easing negative consequences is an essential next phase.
Researchers at Washington State University's Elson S. Floyd College of Medicine suggest in a new report that increasing the amount of time spent asleep immediately after a traumatic experience may be part of a successful treatment regime.
A study just published in Scientific Reports argues that the use of sleep therapeutics following trauma exposure can be beneficial. William Vanderheyden, an assistant research professor and the lead author on the study, says that, “Basically, our study has found that if you can improve sleep, you can improve function."
Vanderheyden made this discovery following a series of experiments in rats in which he and coauthor Christopher Davis examined the links between poor sleep and PTSD. PTSD affects an estimated 8 million Americans each year.
"People with PTSD oftentimes experience nightmares and other types of sleep disturbances, such as frequent awakenings and insomnia," said Vanderheyden. "One thought was that those sleep disturbances may cause further cognitive impairment and worsen the effects of PTSD or the initial trauma. So, we wanted to see whether repairing the sleep disturbances associated with trauma exposure could help alleviate the symptoms of PTSD."
The study by Vanderheyden and Davis used a PTSD rodent model in combination with optogenetics, a technique that uses light-sensitive proteins to control the activity of brain cells.
After going through the PTSD protocol, rats were assigned to two groups. In one group, the researchers used optogenetic stimulation to activate melanin-concentrating hormone (MCH) – a sleep-promoting brain cell type – over a period of seven days. Animals in the second group served as controls.
Comparing the two groups, the researchers found that optogenetic stimulation increased the duration of rapid eye movement (REM) sleep – the sleep phase thought to be important for learning and memory – across the rats' rest and active phases. The researchers then assessed the rats' behavior on a three-day classical conditioning experiment involving a memory task. On day one, rats learned to associate an audible tone with the mildly unpleasant experience of receiving a small foot shock immediately after hearing the tone. After several occurrences, rats would freeze after hearing the tone, anticipating the foot shock. On day two, they heard the tone 30 times without receiving the shock, allowing them to gradually extinguish that memory. On the third day, the researchers played the tone 10 times to test to what extent the previous day's memory extinction had stuck. They found that rats that had received optogenetic stimulation to increase their sleep time had more successfully extinguished the memory, freezing less than control rats.
"This highlights that there is a time-sensitive window when – if you intervene to improve sleep – you could potentially stave off the negative effects of trauma," Vanderheyden says. "Conversely, it seems likely that if you are kept awake after a trauma, this could potentially be harmful to your cognitive function, though we haven't directly tested this as part of our study."
Vanderheyden points out that though prioritizing sleep may not be feasible in victims with potentially life-threatening injuries, increasing sleep in other trauma-exposed populations could practically be done. Military personnel coming back from patrol could be encouraged to sleep and potentially be given sleep-promoting drugs to help them stave off any trauma experienced during their patrol, he said.
Vanderheyden cautioned that although their experiments suggest that manipulating sleep immediately after a trauma may be beneficial, such an intervention may or may not be effective for traumatic experiences that occurred in the more distant past.
Vanderheyden also suggests that the use of antidepressants known as selective serotonin reuptake inhibitors (SSRIs) in people with PTSD may need to be reexamined, as SSRIs are known to suppress REM sleep.
"We may be doing our trauma victims a disservice by prescribing a class of drugs that actually eliminates a potential therapeutic avenue for them by removing their REM sleep when our findings suggest that we should be increasing REM sleep," Vanderheyden says.
To read the original source of the study, click here.
To read the journal article, find it at:
Christopher J. Davis, William M. Vanderheyden. (2020). Optogenetic sleep enhancement improves fear-associated memory processing following trauma exposure in rats. Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-75237-9