Lack of Sleep May Contribute To PTSD Development
A new study presented in a platform session at SLEEP 2015 suggests that treating sleep issues may contribute to a significant enhancement in the treatment of post-traumatic stress disorder (PTSD).
In the study, human volunteers who learned a specific visual cue indicated they were about to receive an electric shock were notably more likely to exhibit prolonged fearful reactions to the signal if they were sleep deprived.
Laura Straus, doctoral candidate at the University of California San Diego and leader of the prospective, parallel group study, believes the study shows that individuals who were sleep-deprived showed a greater inability to “unlearn” the association with circumstances that accompanied an event even when the same circumstances later occur with no trauma, a process known as the extinction of fear.
For the study, volunteers underwent a series of short sessions in which they were shown either a blue or a yellow circle. When shown a blue circle, individuals were delivered a shock. If the circle was yellow, there was no shock.
After these sessions, some participants who were made to stay awake 36 consecutive hours the next day were more likely to still be showing electromyographic patterns in the eyelid (blink EMG) which are known to signal fear.
After the shock training sessions, all participants were again shown the blue and yellow circles in repeated sessions, however, no shocks were delivered over the course of the session. Under most circumstances, the level of fear-responses measured would be decreased due to the fear extinction process.
The last session was similar, with no shocks being delivered. Yet again, the researchers say a decreased fear-response would be expected under normal conditions.
The participants in the study were split into three groups. One group was made to stay awake 36 hours between the shock training session and the first study measuring fear extinction. Another group was deprived of sleep between the fear extinction testing sessions, and another control group was allowed to sleep normally.
According to the results, the group who was deprived sleep between the fear extinction sessions showed no notable abnormalities in the reduction of fear responses during the course of the study.
On the other hand, the group which was deprived of sleep immediately after the shock session showed almost normal levels of extinction but recall of that extinction was notably poorer in the final session. During the final testing, the group exhibited significantly higher blink EMG signals compared to the control group.
Straus says the impairment of extinction recall is similar to the development of PTSD, and the team argues the role of sleep deprivation is especially relevant within the context of military TBI. It is not uncommon for military personnel to go 24 hours without sleep, especially when in battle.
The researchers believe attempting to treat sleep problems may reduce fear responses to traumatic stimuli which could enhance treatment of PTSD.