Involuntary Nerve Activity While Asleep Implicated in PTSD-Related Insomnia
People with post-traumatic stress disorder (PTSD) are unusually likely to develop sleeping problems, especially in the form of insomnia or nightmares. In a study published in December 2014 in the Journal of Traumatic Stress, researchers from Howard University explored the role that nighttime activation of the body’s involuntary nervous system plays in promoting PTSD related insomina. The researchers concluded that changes in the function of both branches of this system contribute significantly to sleep disruptions in affected individuals.
PTSD and Sleeping Problems
The unwanted re-experiencing of trauma-inducing circumstances is one of the main symptoms of PTSD. In some cases, this re-experiencing takes place during waking hours and qualifies as a “flashback.” However, in other cases, the reliving of traumatic experiences occurs during sleep and takes the form of nightmares. Recurring nightmares can substantially decrease the restorative nature of sleep, in addition to destabilizing an individual’s sense of mental well-being. In severe cases, affected people may qualify for a diagnosis of an officially defined mental health condition called nightmare disorder.
Another classic symptom of PTSD is a state known as hyperarousal, which occurs when the body loses control over the “fight-or-flight” reaction that prepares humans for confrontation or rapid escape from danger. The presence of hyperarousal can seriously decrease a person with PTSD’s ability to fall asleep and stay asleep. Individuals with severe forms of these problems may qualify for a separate diagnosis of insomnia disorder. The National Center for PTSD cites a number of additional potential contributors to sleeping difficulties in people with PTSD. These contributors include excessive intake of drugs or alcohol, highly negative thought processes (another core symptom of the disorder) in the hours before sleep and physical health problems that produce serious pain or discomfort.
The Involuntary Nervous System
All of the most critical functions in the human body are under control of the involuntary nervous system, a nerve network that performs its many jobs without relying on conscious effort from the individual. Everyday functions such as your baseline heart rate, breathing rate and digestive processes fall under control of a branch or part of this network called the parasympathetic nervous system. A second branch of the involuntary nervous system, called the sympathetic nervous system, activates in moments of high stress and prepares the body for rapid, potentially life-saving action by doing such things as widening the passageways inside your lungs and speeding up your heart rate in order to increase blood flow to your body. The fight-or-flight response in humans depends on the changes produced by the sympathetic nervous system.
Involuntary Nerve Activity, PTSD and Sleep
In the study published in the Journal of Traumatic Stress, the Howard University researchers used a small-scale project involving 38 young adults to assess the connection between involuntary nervous system function and sleeping difficulties in people with PTSD. Twenty of the study participants had post-traumatic stress disorder. The remaining 18 participants did not have PTSD, although they had lived through traumatic experiences capable of triggering the disorder. The researchers measured the involuntary nervous system function of the members of both groups over the course of a full day. The measurements included readings of parasympathetic nervous system activity during sleep, as well as readings of sympathetic nervous system activity during sleep.
When the researchers compared the two groups, they found that the baseline parasympathetic nervous system output in the PTSD-affected group was unusually low during sleeping hours. They also found that, in the PTSD-affected group, there was an unusual degree of detachment between the time spent sleeping and the activity level inside both the sympathetic nervous system and the parasympathetic nervous system. Overall, the researchers identified two sleep-related problems in the study participants with post-traumatic stress disorder: unusual levels of involuntary nervous system activity during sleeping hours and loss of the normal association between involuntary nervous system activity during sleeping hours and the amount of time actually spent sleeping. The presence of these problems may help explain the underlying mechanisms for PTSD-related insomnia.