How Post-traumatic Stress Disorder Works

Post-traumatic stress disorder is an anxiety disorder. In its simplest terms, it's a specific set of symptoms that result from a traumatic experience. These symptoms must present themselves in a certain way within a certain period of time and for a certain duration to be considered PTSD. Another criterion is how much of an impact the condition has on the patient's everyday life.

The cornerstone symptom of PTSD is re-experience of the trauma (also called intrusive recollection). This means the person is plagued with unwanted memories of the event that so badly scarred him. These memories can come in the form of nightmares (the nightmares of PTSD might not even be "dreams" – there's an idea that it's a neurobiological phenomenon that is interpreted as having been a dream upon awakening), flashbacks and recollections. In each of these instances, memories of the event suddenly and unexpectedly flood the sufferer, and he feels like he's experiencing it all over again. This can be triggered by a cue (such as seeing or hearing a car accident similar to the one the person endured), or it can come unbidden. The person's brain releases chemicals as if he is experiencing the trauma, creating a fear response that's both physical and mental.

Re-experience is one of four main symptoms of adults with PTSD. The other three are avoidance, numbness and hyperarousal [source: National Center for PTSD]:

The tricky part in diagnosing the disorder is that, after a trauma, most people experience the same symptoms as those of a person with PTSD. The difference is that these symptoms fade on their own over time, whereas those with PTSD continue to be plagued by anxiety.

For example, anyone who is in a serious wreck will predictably be shaken by the event. Generally, a person will eventually get past it and move on with his life. He will be able to remember the event without becoming terrified. He will be able to pass by another car wreck without re-experiencing in detail his own. A person with PTSD will not. He is continually negotiating the mental and physical side effects of his traumatic event.

So researchers have attached stipulations to the PTSD diagnosis. Chief among them is that for a person to receive a diagnosis of PTSD, he must have the symptoms for more than one month. These symptoms may show in various ways:

A child with PTSD may have different symptoms. She may behave badly, become needier, and re-experience the event through drawings and explicit re-enactment the trauma. As children with PTSD grow older, research has shown that these symptoms will come to more closely resemble adult symptoms [source: National Center for PTSD].

Who are the people with PTSD? And why are some people more likely than others to develop it? In the next section, we'll find out what researchers have uncovered about susceptibility to PTSD.

Around 70 percent of Americans have endured some traumatic experience within their lifetimes [source: PTSD Alliance]. These may come in the form of a bad car wreck, a rape or an assault. It can be surviving a natural disaster, experiencing a loved one dying unexpectedly, or even killing another person, as in war. Up to 20 percent of those who've suffered go on to experience PTSD [source: PTSD Alliance].

Early researchers believed that all people were at equal risk of developing PTSD after experiencing a trauma. However, further study has revealed that some risk factors may make one person more likely to develop PTSD than another.

One of the biggest risk factors is a prior trauma. People who have already undergone one traumatic experience and then suffer another are more likely to develop PTSD than a person who experiences a single trauma [source: National Center for PTSD]. Why? A class of hormones in the brain called glucocorticoids help control our response to stress, and after a traumatic experience, this hormone can become depleted. When another trauma occurs, and the glucocorticoid levels are already low, the stress response to the experience can be more intensified. This condition can increase the likelihood of the person developing PTSD [source: Kaouane et al].

Personality traits have also been shown to play a part in the development of PTSD. People who have an optimistic outlook on life -- a belief that there's order to the universe, and that other people are generally good -- have less of a chance of developing PTSD after suffering a trauma. So, too, do people who are resourceful -- who tend to take obstacles and challenges head-on [source: NCPTSD].

Conversely, those with problem-avoidance behavior have been shown to have an increased risk of developing PTSD. This indicates that part of the development of PTSD is increased by the avoidance symptom -- the desire to ignore the trauma rather than address it [source: NCPTSD].

People who are college educated are less likely to develop chronic PTSD. So are people who have or had a good relationship with their fathers. At the same time, people who were raised in an abusive environment or have little education are more likely to develop PTSD. It also appears that women are more likely to develop the disorder [source: NCPTSD].

There is also some emerging evidence that PTSD may occur on a genetic level. One gene being looked at is the serotonin transporter gene. A paper indicated that mutations in this gene can have an impact on attention to environmental threats, suggesting that if certain people have a hard time modulating attention to threat in the environment (for instance through hypervigilance) they may be more prone to PTSD [source: Wald et al].

Another study suggests that PTSD may be the result of epigenetics – changes to the function of genes that can happen in a lifetime. A 2009 study of Detroit residents showed that those who fit the criteria for a PTSD diagnosis had six to seven times the regular amount of epigenetic changes to their genes of those in the control group. Most of the genes that had undergone epigenetic change were responsible for immune system function [source: Uddin, et al].

However, the most important factor in the development (or not) of PTSD is the existence of a strong social support network. Time and again, people who have close relationships with those around them have been shown to be much less likely to develop PTSD and more likely to recover from it. Trauma counselor Jacob Lindy referred to this network as a trauma membrane, a group of people who form a protective cover over the person who has suffered the trauma and protect that person from undergoing further damage [source: Satel and Sommers]. For example, a 2008 study indicated that Israeli kids were less depressed after exposure to rocket attacks if they had a solid social group [source: Henrich and Shahar].

It should be noted that what's most important about this social network is how it's perceived by the sufferer. A well-intentioned but overbearing support network will have a less positive effect than one that allows the sufferer to grieve on her own terms [source: Perry].

The world is rife with potentially traumatic situations. Events like Hurricane Katrina, the Columbine High School shootings and the tsunami in Southeast Asia can all lead the people who experienced them to develop PTSD. It's been shown, though, that man-made traumatic events (like Columbine or war) have a greater impact on the incidence of PTSD than natural disasters (like Hurricane Katrina) [source: Galea, et al].

This is just one reason that, on the whole, no other group is more vulnerable to developing PTSD than the military. Experiences like killing other people, handling corpses, being fired upon, witnessing others die and suffering life-threatening injuries can all create trauma in a combatant. The development of PTSD has been shown to be directly related to the intensity of the traumatic experience, and soldiers are often faced with the most stressful of situations on a routine basis. For example, the Vietnam study showed that 15.2 percent of male Vietnam veterans and 8.5 percent of female Vietnam veterans overall had PTSD. However, when only those who had fought in high-intensity combat were evaluated, those numbers jumped to almost 36 percent and 18 percent, respectively. Studies have also shown that people who develop military-related PTSD are more likely to develop it chronically [source: NCPTSD].

Comorbidity (having another disease or disorder) can make someone more vulnerable to PTSD or make existing PTSD worse. Prior drug and alcohol dependency, an existing personality disorder, a family history of mental issues, and brain injuries are all examples of comorbidities. These factors have been shown to directly and negatively affect the impact PTSD has on a person. PTSD can also aggravate an existing drug problem, as well as decrease the likelihood that a person will recover quickly from an injury or illness.

This is of particular concern for some researchers who are studying soldiers fighting in Iraq and Afghanistan. With brain injuries regarded as the "signature wound" of the Iraq war, and most of these injuries coming as the result of a traumatic experience like the explosion of a roadside bomb, the likelihood of these soldiers developing PTSD is increasing. A 2004 study showed that soldiers have a 15 to 17 percent chance of developing PTSD after fighting in Iraq, versus a 9 percent chance before deployment or 11.2 percent after duty in Afghanistan [source: Hoge, et al].

What's more, the military is experiencing a plague of suicides among active and returning military. A Veterans Administration study found that 22 active and former military service people committed suicide each day in 2010 [source: Briggs]. These suicides were not necessarily linked to PTSD in the study, however.

Combatants enlisted today are at added risk due to guerilla warfare during fighting conflicts. In guerilla warfare, the chances for witnessing and taking part in abusive violence, atrocities and civilian casualties increases, and all of these factors have been shown to raise the likelihood that a person will develop post-traumatic stress disorder as a result [source: NCPTSD].

Imagine sitting with your platoon, taking a break from patrol in the desert of Iraq. The sky is clear and blue. The sun is shining, and it's hot and dusty, but you and your buddies are cracking jokes. On the stereo, your favorite song is playing. You're still on guard, but for once you feel kind of relaxed.

Suddenly, out of nowhere, you encounter enemy fire. As shells zip past you and you return fire, you catch glimpses of the enemy firing from behind a burned-out truck. A buddy takes a bullet in his stomach and falls beside you, and you pull him to safety behind your patrol's armored car. You return fire again, and this time it's clear to you that you killed one of the enemies. After a few more minutes, your patrol manages to flush the enemy from behind the burned-out truck, killing several more people.

You're alive, unhurt. Your buddy has died.

As time progresses, you find that you can't escape the experience. You're haunted by your friend who died and the man you killed. Hearing your favorite song now, the one that played on the radio just before the fight, reminds you of every detail. The still of the sunny day, one of the things that had calmed you just before the fight, comes to be remembered as ominous.

Our fear memories are among our most powerful. They can even become distorted and distort other memories associated with the experience. People with PTSD don't wish to be reminded of them, and they don't feel like anyone can understand what they've gone through, which leads to a sense of isolation. This is what makes PTSD so difficult to treat. The memories of the traumatic event become so largely distorted that they become overwhelming in their importance and magnitude. Isolation keeps people with PTSD from their family, friends and counselors.

Some treatments have been proven to combat these symptoms of PTSD. Two of the most widely accepted forms of psychotherapy for treating the disorder are cognitive processing therapy (CPT) and exposure therapy. The aim of these treatments is cognitive restructuring. Through this process, exaggerated memories are reduced back to a manageable size. In the experience of PTSD, the enemies in the above scenario be seen as faceless phantoms; the wounds of the friend may become gorier. Cognitive restructuring helps the patient remember the event on a more acceptable level. In the CPT setting, the therapist may focus on the valor shown by the solider when he retrieved his friend in the attempt to save his life -- adding balance to the memory of the experience and helping to develop perspective [source: Perry]. CPT also allows the person to gain control of his unwanted recollections by allowing these memories to occur at a designated time of day, or investing protective associations in an everyday object.

In exposure therapy, patients are asked to purposely re-experience their trauma over and over -- either in a doctor's office or in the outside world in a setting similar to the one where they experienced their trauma. This is called imaginal therapy. The soldier in the scenario may be asked to recount the experience in detail repeatedly. The song that played which reminds him so much of the incident may be played repeatedly as well [source: NCPTSD].

Exposure therapy is based upon the idea that it's avoidance that continues to fuel the symptoms associated with PTSD. By bringing these memories to the forefront and addressing them, this therapy aims to bring about fear extinction in the patient, a process that takes place in the amygdala (the part of the brain that allows us to create our fear memories) and normally allows people to stop having a full, physical reaction to stimuli associated with the traumatic experience. Some find CPT more desirable than exposure therapy because the patient doesn't have to identify a specific trauma for it to work, which is of course required in exposure therapy.

A combination of counseling and medication is often used to treat post-traumatic stress disorder.

Two versions of one type of drug, known as selectiveserotonin reuptake inhibitors (SSRIs), are already being used to treat some symptoms of PTSD. SSRIs have been shown to reduce depression and anxiety in patients and two SSRIs, Zoloft and Paxil, are the only medications approved by the U.S. Food and Drug Administration for treatment of PTSD [source: NCPTSD].

While SSRIs help to alleviate symptoms and can make people with PTSD more receptive to counseling, another drug, D-cycloserine (DCS), which is used to treat tuberculosis, may have an indirect effect on treating PTSD. DCS is known for its ability to enhance learning by affecting a type of receptor in the brain. Researchers hope that when used in conjunction with exposure therapy the drug may help separate memories from their association to a stimulus (memory extinction) and diminish the fear response in PTSD patients[source: deKline]. Prazosin, a decades-old blood pressure medication, has impressive efficacy in reducing nightmares [source: WebMD]

Researchers are also studying propranolol, a beta-blocker, to determine its effects on PTSD symptoms like hyperarousal and their secondary effects like sleeplessness. The drug may also prove to be useful as an agent that can block the creation of fear memories from an event [source: Lavine].

In the next section, we'll learn about some cutting-edge research and therapy for PTSD.

The field that may yield the most possibilities for treating PTSD in the future is neurology.

Studying the brain's functions has already turned up some interesting facts about how we process our fear response. One chemical that has been studied is called stathmin, and it allows us to form fear memories from our experience. In a laboratory experiment, researchers treated mice to diminish their levels of stathmin. Those mice with lowered levels were less likely to be affected by panic (and less likely to "freeze") when confronted with traumatic experiences later [source: NIMH].

Another chemical, gastrin-releasing peptide, has been shown to signal a response in the brain. Research suggests that a lack of this chemical could lead to an increased chance that a person will form stronger fear memories [source: NIMH].

How we create and maintain our fearful memories of experiences is at the heart of physiological research on PTSD. Investigation into the amygdala has shown that this part of our brain helps us to learn how to not fear, as well as to fear. The ventromedial prefrontal cortex (PFC) appears to maintain our long-term fear memories. Researchers have found that the size of this part of the brain may be related to the likelihood a person keeps fear memories after a traumatic event [source: NIMH]. Of course, environmental and social factors have their parts to play in whether people with genetic predispositions to PTSD actually get it.

Researchers at Fort Bragg, N.C., have studied soldiers who handle stressful situations better than others and believe they have found a chemical that's responsible for the difference. Neuropeptide Y is thought to be the brain's own anti-anxiety drug. As we're exposed to a stressful or traumatic situation, our levels of this drug become depleted. The more depleted it becomes, the more fearful and less prone to feel we can overcome an obstacle we become. Scientists are trying to synthesize neuropeptide Y to restore a person's depleted levels after a traumatic situation, and possibly guard against the development of PTSD [source: NCPTSD].

Stellate ganglion blocks have also been tested. This procedure uses a local anesthetic injected above the clavicle to block the function of sympathetic nerves (the same ones responsible for the fight-or-flight response). A 2008 study found that seven of nine patients given the block experienced relief of their PTSD symptoms, including one patient who had been suicidal for the previous two years. However, the benefits appeared to fade after two months [source: Hicky, et al].

MDMA (also known as ecstasy) has also been shown to lessen the effects of PTSD. The majority of patients in a 2012 study of the drug showed relief from their symptoms; some of these patients hadn't experienced any relief from other courses of treatments they'd taken [source: The Guardian]. And transcranial magnetic stimulation (TMS) has been shown to improve PTSD conditions as well. The authors of a 2004 study of 20 male and female patients suffering from PTSD as a result of events like combat, assault and sexual abuse believe that the effects were the result of the magnetic coil stimulating neurons in the brain [source: VA Research Currents].

Also, remember that study of Detroit PTSD sufferers that found they had epigenetic changes to their immune system genes? There is growing evidence that injecting a person who has recently undergone a trauma (within the first few hours) with a low dose of regular hydrocortisone, a corticosteroid that suppresses the immune response, can prevent PTSD from taking hold later on. This is new stuff and the studies are small, but the results are encouraging [source: Delahanty, et al].

Virtual reality is also being used to help treat people with PTSD. It has reduced chronic PTSD symptoms in Vietnam veterans and is particularly useful for people who can't or won't access their emotions in therapy. A case study used virtual reality simulations of the Sept. 11 attacks on the World Trade Center as part of exposure therapy to help one woman recover from PTSD. She was exposed to her traumatic memory not by her own recollections, but as an active observer (for instance, virtual planes flew into virtual towers). The result was very positive. Her PTSD symptoms decreased by 90 percent [source: HITL].

Research into the viability and usefulness of delivering counseling via the Internet or by phone is also being conducted. This kind of counseling could be helpful in cases of mass disasters that affect large numbers of people by delivering counseling to many people at the same time.