Posttraumatic Stress Disorder Causes & Risk Factors

Conditions & Diseases: Psychological & Mental Health

Posttraumatic Stress Disorder

Posttraumatic Stress Disorder Causes and Risk Factors

Researchers are still trying to understand what causes and increases the risk of developing posttraumatic stress disorder. However, it is believed that PTSD is caused by a combination of several factors including environmental, biological and psychological,

Environmental factors: Posttraumatic stress disorder is associated with the exposure to a traumatic event. Approximately, 60.7 percent of men and 51.2 percent of women have experienced at least one traumatic event during their life. However, encountering a traumatic event or more during the life span does not necessarily mean that the person will develop the disorder. According to statistics, only 5 percent of men and 10 percent of women are affected by PTSD.

The risk of developing the disorder seems to be influenced by:

The severity of the traumatic event.
The duration of the traumatic event
The proximity to the traumatic event (whether was experienced directly or witnessed).
The type of the traumatic event.
Whether the traumatic event was deliberately planned or accidental.
Whether the person was previously exposed to other traumatic events.

Biological factors: There are several biological theories that try to explain why people develop posttraumatic stress disorder. Some researchers suggest that PTSD symptoms can be caused by dysfunctions of the amygdala. The amygdala is a structure of the brain and part of the limbic system that is involved in the expression of emotions (such as fear), autonomic reactions (such as increased heart rate and blood pressure, the startle response) and emotional memory. Dysfunctions in the limbic system can affect the functions of other brain structures such as hypothalamus and neocortex. Hypothalamus and neocortex are two brain structures that control regulatory functions such as sleep, rest, activity, feeding, and reproductive cycle, and monitor and assess what is new, dangerous, and gratifying.

Studies conducted on the influence of neurotransmitters in the development of PTSD symptoms suggest that the human brain, when exposed to trauma, undergoes intense bio-chemical changes that can lead to permanent impairments of the normal functions of the nervous system. A traumatic event can alter the normal secretion of certain neurotransmitters, such as epinephrine, cortisol, norepinephrine, serotonin, and endorphins.

Epinephrine and cortisol are two neurotransmitters produced by the adrenal gland and they play an important role in the body's reaction to stress. Epinephrine is known as the "fight or flight" hormone, because it helps the body to cope with stressful events. Cortisol, also known as the "stress hormone", is produced when the individual faces threatening situations by increasing the blood pressure and the sugar level in the blood.

Norepinephrine is a neurotransmitter that helps the brain to be alert and solve problems, but together with epinephrine are also known as stress hormones. They are released in the brain when the body is exposed to stressful situations or trauma, but when present in high amounts can cause PTSD symptoms to develop. Increased levels of stress hormones also affect the memory. Researchers believe that amnesia, common in individuals with PTSD, is caused by excessive levels of norepinephrine released in the brain during trauma.

Serotonin is another neurotransmitter that can play an important role in PTSD symptoms. Reduced amounts of serotonin is associated with hyperarousal when exposed to new stimuli. Serotonin is also associated with hostility, impulsivity, and self-directed aggression.

Some studies also suggest a possible bio-chemical component involved in emotional numbing, a symptom common among individuals with PTSD. Emotional nonresponsivness can be caused by increased amounts of endogenous opiates (endorphins and enkephalins) which inhibit the pain and reduce panic. Opiates are released in the brain when individuals exposed to prolonged or repeated trauma encounter stimuli that trigger memories of the traumatic event.

Some individuals with PTSD have high levels of free tyrosine and total thyroxine, two thyroid hormones. These hormones are produced during extremely stressful events such as an earthquake, fire, or combat, and can increase the rate of metabolism.

Psychological factors: An important role among the risk factors of PTSD is the mental health status of the individual. The risk of developing PTSD increases if the person:

Was previously diagnosed with borderline personality disorder or dependent personality disorder.
Has a pre-existing anxiety disorder or is depressed.
Experienced pervious traumas.
Has a low self-esteem.

Also, studies suggest a possible connection between certain personality traits and PTSD symptoms. A study conducted on soldiers revealed that PTSD symptoms seemed to be more severe when the individual was exposed to a higher number of stressful events (shooting or dead people), but those that scored high on personality traits such as negativism and paranoia prior to deployment tend to show more signs of PTSD. Researchers believe that these results suggest that a hostile person perceives more "personal menace" in traumatic events and an anxious person may cope less effective with stressful events. Another study conducted on firefighters suggested that traits such as high levels of hostility and low levels of self-efficacy can influence the development of stress-related symptoms. According to the study, "individuals with low levels of hostility may have better social coping abilities than those with high levels. Also, individuals with high levels of self-efficacy and confidence may be able to impose meaning on their traumatic experiences, thereby fostering recovery for them".(2)

Article by Alina Morrow
MS Psychology
Medical Writer
OmniMedicalSearch.com