PTSD – Post Traumatic Stress Disorder

Post Traumatic Stress Disorder (PTSD) is an Anxiety Disorder that can develop after exposure to one or more terrifying events in which grave physical harm occurred or was threatened. It is a severe and ongoing emotional reaction to an extreme psychological trauma. 

The trauma may involve someone’s actual death or a threat to the patient’s or someone else’s life, serious physical injury, or threat to physical and/or psychological integrity. In some cases it can also be from profound psychological and emotional trauma, apart from any actual physical harm. The PTSD sufferer is affected to a degree that usual psychological defenses are incapable of coping. 

Reports of battle-associated stress appear as early as the 6th century BC. PTSD-like symptoms have been recognized in many combat veterans in many conflicts since. These symptoms have been called shell shock, traumatic war neurosis, and Post-Traumatic Stress Syndrome (PTSS). The modern understanding of PTSD dates from the 1970s, largely as a result of the problems that were still being experienced by Vietnam veterans.

The term Post Traumatic Stress Disorder was coined in the mid 1970s. Early in 1978, the term was used in a working group finding presented to the Committee of Reactive Disorders of the American Psychiatric Association. The term was formally recognised in 1980 in the third edition of the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association.

What are the diagnostic criteria for PTSD?

PTSD is unique among psychiatric disorders in that it is identified not only by symptoms, but also by the precursor of the illness — the traumatic event. Therefore, identifying people with PTSD can be difficult, and this disorder often goes unrecognized.

Many times people are reluctant or unable to discuss the traumatic event that leads up to PTSD, making an accurate diagnosis difficult. Talking about the trauma may bring forth painful emotions. Domestic violence and sexual abuse are subjects many feel uncomfortable talking about. Others feel shame and guilt related to the event, and social pressures to just “deal with” the symptoms that come afterward.

Persons with PTSD often have other disorders, such as substance abuse and depression. These other disorders share some of the symptoms of PTSD and can also make diagnosis difficult.

The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), a publication of the American Psychiatric Association, is the standard psychiatric diagnostic reference in the United States and much of the world. It lists the diagnostic criteria for PTSD in section 309.1 (please note that references to children have been removed): (1)

A. The person has been exposed to a traumatic event in which both of the following have been present: 

(1) the person experienced, witnessed, or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of self or others 

(2) the person’s response involved intense fear, helplessness, or horror. 

B. The traumatic event is persistently reexperienced in one (or more) of the following ways: 

(1) recurrent and intrusive distressing recollections of the event, including images, thoughts, or perceptions. 

(2) recurrent distressing dreams of the event.

(3) acting or feeling as if the traumatic event were recurring (includes a sense of reliving the experience, illusions, hallucinations, and dissociative flashback episodes, including those that occur upon awakening or when intoxicated). 

(4) intense psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event.

(5) physiological reactivity on exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event.

C. Persistent avoidance of stimuli associated with the trauma and numbing of general responsiveness (not present before the trauma), as indicated by three (or more) of the following: 

(1) efforts to avoid thoughts, feelings, or conversations associated with the trauma 

(2) efforts to avoid activities, places, or people that arouse recollections of the trauma 

(3) inability to recall an important aspect of the trauma 

(4) markedly diminished interest or participation in significant activities 

(5) feeling of detachment or estrangement from others 

(6) restricted range of affect (e.g., unable to have loving feelings) 

(7) sense of a foreshortened future (e.g., does not expect to have a career, marriage, children, or a normal life span)

D. Persistent symptoms of increased arousal (not present before the trauma), as indicated by two (or more) of the following: 

(1) difficulty falling or staying asleep 

(2) irritability or outbursts of anger 

(3) difficulty concentrating 

(4) hypervigilance

(5) exaggerated startle response

E. Duration of the disturbance (symptoms in Criteria B, C, and D) is more than one month.

F. The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

The following specifiers may be used to specify onset and duration of the symptoms of Post Traumatic Stress Disorder:

Acute.  This specifier should be used when the duration of symptoms is less than 3 months.
Chronic.  This specifier should be used when the symptoms last 3 months or longer.
With Delayed Onset.  This specifier indicates that at least 6 months have passed between the traumatic event and the onset of the symptoms.

Acute Stress Disorder can be a precursor to PTSD, but is a separate diagnosis. A person with Acute Stress Disorder may experience difficulty concentrating, feeling detached from their body, experience the world as unreal or dreamlike, or have increasing difficulty recalling specific details of the traumatic event (dissociative amnesia). In addition, at least one symptom from each of the symptom clusters for PTSD are present. Reminders of the trauma are avoided, and hyperarousal in response to stimuli reminiscent of the trauma is present. The symptoms for Acute Stress Disorder must last a minimum of 2 days and a maximum of 4 weeks. (2)

What is the prevalence of PTSD?

The National Institute of Mental Health (NIMH) says that PTSD currently affects about 7.7 million American adults.(3) The Mayo Clinic states that 7 to 8 percent of the population, about 24 million, will have PTSD at some time in their lives. (4) This represents a small portion of those who have experienced a traumatic event in their lives: 61 percent of men (185 million) and 51 percent of women (155 million) have reported at least one traumatic event. Women are more likely to develop PTSD than men. (5)

The Anxiety Disorder Association of America (ADAA) states that 67% of those exposed to mass violence have been shown to develop PTSD, a higher rate than those exposed to other types of traumatic events, such as natural disasters. (6) In 2004 at least 13 percent of people living in Lower Manhattan still had PTSD in relation to the 9/11 attacks three years after the events. (7) Around 4 percent of people across the country appear to have PTSD related to those attacks. (8). People in New Orleans who suffered through Hurricane Katrina have an incidence of PTSD 10 times greater than the general public. (9)

The National Vietnam Veterans Readjustment Study (NVVRS) states that the estimated lifetime prevalence of PTSD among American Vietnam theater veterans is 31 percent for men and 28 percent for women. An additional 23 percent of men and 21 percent of women have had partial PTSD at some point in their lives. Thus, more than half of all male Vietnam veterans and almost half of female veterans have experienced “clinically serious stress reaction symptoms.” In 1986-88, when the Survey was conducted, 15 percent of all male veterans (479,000 out of 3,140,000 men who served in Vietnam) and 8 percent of all female veterans (610 out of 7,200 women who served) currently had cases of PTSD. (10)

The Rand Corporation and the California Community Foundation released a study in April, 2008, the first to try and assess the mental health of the 1.65 million service members who have been deployed in Iraq or Afghanistan. Of these, nearly 20 percent, or 300,000, report symptoms of PTSD or major depression, a figure disproportionately high compared with those with physical injuries. Despite the symptoms, only slightly more than half have sought treatment. Many say they do not seek treatment because they fear it will harm their careers. 

The Rand study states that rates of PTSD and depression were highest among Army soldiers and Marines, and among service members who were no longer on active duty (people in the reserves and those who had been discharged or retired from the military). Women, Hispanics and enlisted personnel all were more likely to report symptoms of PTSD and major depressions, but the single best predictor of PTSD and depression was exposure to combat trauma while deployed. (11)

What are the types of PTSD?

There are five main types of PTSD: normal stress response, acute stress disorder, uncomplicated PTSD, comorbid PTSD and complex PTSD. (12)

Normal Stress Response

The normal stress response occurs when healthy adults have been exposed to a single traumatic event in adulthood. They experience symptoms such as intense bad memories, emotional numbing, feelings of unreality, being cut off from relationships or bodily tension and distress. Such individuals usually achieve complete recovery within a few weeks.

Acute Stress Disorder

Acute stress disorder is characterized by panic reactions, mental confusion, dissociation, severe insomnia, suspiciousness, and being unable to manage even basic self care, work, and relationship activities. Relatively few survivors of single traumas have this more severe reaction, except when the trauma is a lasting catastrophe that exposes them to death, destruction, or loss of home and community. (See “What are the diagnostic criteria for PTSD?” above for more information.)

Uncomplicated PTSD

Uncomplicated PTSD involves persistent reexperiencing of the traumatic event, avoidance of stimuli associated with the trauma, emotional numbing, and symptoms of increased arousal.

Comorbid PTSD

PTSD comorbid (the simultaneous presence of two chronic conditions) with other psychiatric disorders is much more common than uncomplicated PTSD. PTSD is usually associated with at least one other major psychiatric disorder such as depression, alcohol or substance abuse, Panic Disorder, and other Anxiety Disorders.

Complex PTSD

Complex PTSD (sometimes called “Disorder of Extreme Stress”) is found among individuals who have been exposed to prolonged traumatic circumstances, especially during childhood. These people often are diagnosed with Borderline or Antisocial Personality Disorder or dissociative disorders. They exhibit behavioral difficulties such as impulsivity, aggression, sexual acting out, eating disorders, alcohol or drug abuse, and self-destructive actions; extreme emotional difficulties such as intense rage, depression, or panic; and mental difficulties such as fragmented thoughts, dissociation, and amnesia. The treatment of such patients often takes much longer than other PTSD treatments, may progress at a much slower rate, and requires a sensitive and highly structured treatment program delivered by a team of trauma specialists.

What are the differences between PTSD and other mental disorders?

As mentioned above, PTSD is unique among psychiatric disorders in that it is identified not only by symptoms, but also by the precursor of the illness — the traumatic event. However, many of the symptoms of PTSD are similar to those of other disorders, particularly Obsessive-Compulsive Disorder (OCD), Adjustment Disorder, and Acute Stress Disorder.

Both PTSD and OCD have recurrent, intrusive thoughts as a symptom. The types of thoughts are one way to distinguish between these two disorders. Thoughts present in OCD do not usually relate to a past traumatic event. With PTSD, the thoughts are invariably connected to a past traumatic event. 

PTSD symptoms can also seem similar to Adjustment Disorder because both are linked with Anxiety that develops after exposure to a stressor. With PTSD, this stressor is a traumatic event. With Adjustment Disorder, the stressor does not have to be severe or outside the “normal” human experience. (13)

A similar disorder in terms of symptoms is Acute Stress Disorder. The major differences between the two disorders are that Acute Stress Disorder symptoms last from two days to four weeks, and a fewer number of traumatic symptoms are required to make the diagnosis as compared to PTSD. (14)

What is the course or prognosis for PTSD?

PTSD can occur at any age, including childhood. Symptoms usually begin within the first 3 months after the trauma, although there may be a delay of months, or even years, before symptoms appear. Frequently, the disturbance initially meets the criteria for Acute Stress Disorder in the immediate aftermath of the trauma (see above, “What is the diagnostic criteria for PTSD?” for more information). 

The prognosis of PTSD varies from individual to individual. (15) The symptoms of the disorder and the relative predominance of re-experiencing, avoidance and hyperarousal may vary over time. Approximately half of PTSD sufferers experience complete recovery within 3 months. Others have persistent symptoms for longer than 12 months after the trauma. (16)

What are the dangers of PTSD?

More so than other Anxiety Disorders, PTSD puts a person at risk for an array of mental and physical disorders. It can disrupt a person’s whole life, from their job to relationships to the enjoyment of everyday activities. 

Persons with PTSD often have other mental disorders as well, which makes it difficult for clinicians to diagnose and treat it. In particular, major depression and substance abuse are common in people with PTSD. There may also be an increased risk of Panic Disorder, Agoraphobia, Obsessive-Compulsive Disorder, Social Phobia and Somatization Disorder (recurrent and multiple medical symptoms with no discernible organic cause). Scientists are uncertain to what extent these co-occurring disorders are present before or come after the traumatic event and the development of PTSD. (17)

When exposure to trauma has been long-standing, persons may develop certain enduring patterns of behavior or traits. These include difficulty in trusting others, irregular moods, impulsive behavior, shame, decreased self-esteem and unstable relationships. Persons with PTSD may find it difficult to talk about symptoms with those who did not go through the same trauma. Sometimes, guilt about surviving or about acts done in order to survive can also cause increased isolation and tension in interpersonal relationships. (18)

Significant interpersonal difficulties are common in persons with PTSD. Symptoms of estrangement, irritability, anger, emotional numbing and other mental disorders play havoc with relationships. Emotional numbing alone is devastating to relationships. It presents itself as a lack of interest in activities that used to be enjoyed (anhedonia), emotional deadness, and distancing oneself from people. It is no wonder that PTSD leaves a trail of broken homes and estrangement from those one once held dear. 

The NVVRS report showed that 40 percent of Vietnam veterans had been divorced once, and 10 percent had two or more divorces. High levels of marital problems were reported by 14 percent, and 23 percent had high levels of parental problems. (19) In addition, studies have shown that PTSD increases the risk that one’s offspring will have PTSD as well, with some of the same brain changes that PTSD sufferers have. (20)

Almost half of male Vietnam war veterans with long-term PTSD had been in jail once by the year 1988, and 34 percent more than once, according to the NVVRS, and 11.5 percent had been convicted of a felony. (21)

The NVVRS also reported that the estimated lifetime prevalence of alcohol abuse or dependence among male Vietnam war veterans was 39 percent, and the estimate for abuse or dependence in 1988, when the report was released, was 11 percent. The estimated lifetime prevalence for drug abuse or dependence was 6 percent, and 2 percent were abusing drugs or dependent at the time of the report’s release.

Persons with PTSD also often have physical disorders. They visit the doctor for physical complaints at a rate much higher than the general population, among them hypertension and asthma. (22) 

Vietnam veterans who experienced PTSD are twice as likely to die of heart disease than veterans without PTSD, a recent Geisinger study finds. There is no reason to believe that other sufferers’ experience with PTSD will be any different. One researcher said, (23)

Increased levels of stress hormones and less cortisol from PTSD are a bad combination. Basically, PTSD just cooks your arteries in this situation.

Another recent study found that simply having PTSD was just as good an indicator of a person’s long-term health status as other indicators, such as an elevated white blood cell count, for predicting inflammations, major infections, or a serious blood disorder such as leukemia. The Senior Investigator for the study, Joseph Boscarino, said,  (24)

Exposure to trauma has not only psychological effects, but can take a serious toll on a person’s health status and biological functions as well. PTSD is a risk factor for disease that doctors should put on their radar screens.

What are the symptoms of PTSD?

Post Traumatic Stress Disorder symptoms may include: (25) (26) (27)

• Flashbacks, or reliving the traumatic event for seconds, minutes or even days at a time; often triggered by ordinary occurrences, such as a door slamming, smells or the weather
• Shame or guilt that they survived and others didn’t, or at what had to be done to survive
• Upsetting dreams about the traumatic event
• Trying to avoid thinking or talking about the traumatic event
• Avoiding situations that remind them of the original incident; anniversaries of the incident are often very difficult
• Feeling emotionally numb, especially in relation to people with whom they used to be close
• Irritability or anger
• Becoming more aggressive, or even becoming violent.
• Have trouble feeling affectionate
• Poor relationships
• Social withdrawal
• Self-destructive behavior, such as drinking too much
• Hopelessness about the future
• Feeling permanently damaged
• Loss of previously sustained beliefs, for example, religious beliefs
• Depression
• Trouble falling or staying asleep
• Memory problems
• Trouble concentrating or completing tasks
• Being easily startled or frightened
• Feeling constantly threatened
• Not enjoying activities they once enjoyed
• Hearing or seeing things that aren’t there

PTSD symptoms can come and go. A person can have more symptoms during times of higher stress or when they experience symbolic reminders of what they went through. For example, some people whose PTSD symptoms had been gone for years saw their symptoms come back again with the terrorist attacks in the U.S. on Sept. 11, 2001.

What are the causes of PTSD?

Although PTSD begins after a traumatic event, other factors also play an important role. The severity, type, and circumstances of the traumatic event may determine whether or not a person develops PTSD. The disorder may be especially severe or long lasting when the stressor is of human design (e.g., torture, rape). The likelihood of developing this disorder may increase as the intensity of and physical proximity to the stressor increase. (28)

The traumatic events most often associated with PTSD are: (29 )

• For men: rape, combat exposure, childhood neglect and childhood physical abuse
• For women: rape, sexual molestation, physical attack, being threatened with a weapon and childhood physical abuse

Researchers are still trying to better understand what causes someone to get post-traumatic stress disorder. As with most mental illnesses, PTSD is probably caused by a complex mix of: (30)

• Changes in the natural chemicals in the brain and body
• Biology and genetics
• Life experiences
• Personal temperament

Biochemical Causes

PTSD displays biochemical changes in the brain and body that differ from other psychiatric disorders. These chemical changes center around cortisol, a hormone produced by the adrenal gland. PTSD sufferers have a lower secretion of cortisol than others, and the ratio of cortisol to norepinephrine, a brain chemical, is higher. Low cortisol levels may predispose individuals to PTSD following trauma. Because cortisol is important to restoring balance after a stressful event, it is thought that trauma survivors with low cortisol experience a longer and more distressing response, setting the stage for PTSD.

The low level of cortisol suggests that there is an abnormality in the functioning of the hypothalamus, the pituitary gland and the adrenal gland (called the HPA axis), which work together. Some researchers have associated the response to stress in PTSD with long-term exposure to high levels of norepinephrine and low levels of cortisol, a pattern associated with improved learning in animals. Translating this reaction to human conditions gives an explanation for PTSD via a maladaptive learning pathway to fear response through a hypersensitive, hyperreactive and hyperresponsive HPA axis. (31)

Brain Structure Changes

In addition to biochemical changes, PTSD also involves changes in the brain’s structure. Combat veterans of the Vietnam war with PTSD showed an 8% reduction in the volume of their hippocampus in comparison with veterans who suffered no such symptoms. (32)

The brain’s amygdala is strongly involved in the formation of emotional memories, especially fear-related memories. Neuroimaging studies have shown structural and functional changes to the amygdala in PTSD. This causes researchers to believe that the hyperarousal of the amygdala in PTSD is insufficiently checked by the brain’s prefrontal cortex and hippocampus.

Genetic Causes

PTSD runs in families. A twin study done with 4042 Vietnam era veterans showed that in identical twins, there was an increased risk of one twin getting PTSD if the other did. Non-identical twins did not show this tendency. (33) 

A study of the offspring of PTSD sufferers show that the children, too, have the reduced cortisol output of their parent with PTSD, giving them a predilection for the disorder. This leads researchers to believe that there is a genetic link that causes this reduced output. (34)

Researchers with the Geisinger Health System have discovered that combat veterans with an extreme level of mixed handedness were nearly twice as likely to develop PTSD after combat compared to veterans who use both hands less often. Those with both an extreme mixed handedness and high combat exposure were nearly five times as likely to have PTSD. Joseph Boscarino, PhD, MPH the study’s principal investigator, said, (36)

These findings suggest the possibility of a pre-existing biological vulnerability for PTSD. We know generally what type of soldier is likely to suffer from PTSD, before they go into combat.

Because of the difficulty in performing genetic studies on a condition with a major environmental factor (i.e. trauma), genetic studies of PTSD are in their infancy.

What is the treatment for PTSD?

Treatment of post-traumatic stress disorder can be very effective and help regain a sense of control over life. With successful treatment, a person can also feel better about theirself and learn ways to cope if any symptoms arise again.

Post-traumatic stress disorder treatment often includes both psychotherapy and medication. This combined approach can help improve a person’s symptoms and teach skills to cope better with the traumatic event and its aftermath.

Psychotherapy

Several forms of therapy may be used to treat adults with PTSD. Which form is best for an individual depends on the symptoms and situation. One may try one type and then a different type of therapy, or combine elements of several. A person may also try individual therapy, group therapy or both. Group therapy can offer a way to connect to others going through similar experiences.

Many methods of therapy have been developed for survivors of trauma. All methods share the following guidelines: (36)

• Therapy always is individualized to meet the specific concerns and needs of each unique trauma survivor. It is based upon careful interview and questionnaire assessments at the beginning of, and during treatment.
• Trauma therapy is done only when the patient is not currently in crisis. If a patient is severely depressed or suicidal, experiencing extreme panic or disorganized thinking, in need of drug or alcohol detoxification, or currently exposed to trauma (such as by ongoing domestic or community violence, abuse, or homelessness), these crisis problems must be handled first.
• When a shared plan of therapy has been developed within an atmosphere of trust and open discussion by the patient and therapist, a detailed exploration of trauma memories is done, This enables the survivor to cope with post-traumatic memories, reminders, and feelings without feeling overwhelmed or emotionally numb.
• The goal of “trauma focused” exploration is to enable the survivor to gain a realistic sense of self-esteem and self-confidence in dealing with bad memories and upsetting feelings caused by trauma. Trauma memories usually do not go away entirely as a result of therapy, but become manageable with new coping skills.
• Trauma exploration can be done in several ways, depending upon the type of post-traumatic problems a survivor is experiencing. (See “What are the types of PTSD?” above for more information.) Uncomplicated PTSD involves persistent reexperiencing of the traumatic event, avoidance of stimuli associated with the trauma, emotional numbing, and symptoms of increased arousal. It may respond to group, psychodynamic, cognitive-behavioral, pharmacological or combination approaches.

Brief Psychodynamic Psychotherapy is a type of therapy focusing on the emotional conflicts caused by the traumatic event. Through the retelling of the traumatic event to a calm, empathic, compassionate and non-judgemental therapist, the patient achieves a greater sense of self-esteem, develops effective ways of thinking and coping, and more successfully deals with the intense emotions that emerge during therapy. The therapist helps the patient identify current life situations that set off traumatic memories and worsen PTSD symptoms.

There are two Cognitive-Behavioral Therapy (CBT) approaches: exposure therapy and cognitive-behavioral therapy. 

Exposure therapy involves therapeutically confronting a past trauma by either: 

• Repeatedly imagining it in great detail
• Going to places that are strong reminders of the trauma experience(s) 

Exposure therapy is intended to help the patient face and gain control of the fear and distress that was overwhelming in the trauma. It must be done very carefully in order not to re-traumatize the patient. In some cases, trauma memories or reminders can be confronted all at once (”flooding”). For other individuals or traumas it is preferable to work gradually up to the most severe trauma by using relaxation techniques and either starting with less upsetting life stressors or by taking the trauma one piece at a time (”desensitization”).

Cognitive-behavioral therapy involves:

• Learning skills for coping with anxiety, such as breathing retraining or biofeedback
• Learning skills for coping with negative thoughts (”cognitive restructuring”)
• Managing anger
• Preparing for stress reactions (”stress inoculation”)
• Handling future trauma symptoms
• Dealing with urges to use alcohol or drugs when they occur (”relapse prevention”)
• Communicating and relating effectively with people (”social skills” or marital therapy)

Exposure and cognitive-behavioral therapies are often used together, although it is important not to use too many different therapy methods because this can cause the patient to feel overwhelmed and confused.

Group treatment is practiced in VA PTSD Clinics and Veteran Centers for military veterans and in mental health and crisis clinics for victims of assault and abuse. A group of peers provides an ideal therapeutic setting because trauma survivors are able to risk sharing traumatic material with the safety, cohesion, and empathy provided by other survivors. It is often much easier to accept confrontation from a fellow trauma survivor than from a professional therapist who never went through those experiences first-hand. 

As group members achieve greater understanding and resolution of traumatic themes, they often feel more confident and able to trust. As they work through trauma-related shame, guilt, rage, fear, doubt, and self-condemnation, they prepare themselves to focus on the present rather than the past. Telling one’s story (the “trauma narrative”) and directly facing the grief, anxiety, and guilt related to trauma enables many survivors to go on with their lives rather than getting stuck in unspoken despair and helplessness.

Medications

Drug therapy can reduce the anxiety, depression, and insomnia often experienced with PTSD. In some cases it may help relieve the distress and emotional numbness caused by trauma memories. Several kinds of antidepressant drugs have achieved improvement in most (but not all) clinical trials, and some other classes of drugs have shown promise. 

At this time no particular drug has emerged as a definitive treatment for PTSD, although medication is clearly useful for symptom relief, making it possible for patients to participate in group, psychodynamic, cognitive-behavioral, or other forms of psychotherapy.

FOOTNOTES

(1) Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Arlington, VA: American Psychiatric Association. 1994.

(2) Psych Central. (2008). Acute Stress Disorder. Retrieved July 13, 2008 from Psych Central Web site: http://psychcentral.com/disorders/sx44.htm

(3) National Institute of Mental Health. (2008). Post-Traumatic Stress Disorder. Retrieved July 11, 2008 from National Institute of Mental Health Web site: http://www.nimh.nih.gov/health/topics/post-traumatic-stress-disorder-ptsd/index.shtml

(4) Mayo Clinic Staff. (2007, April 12). Post-traumatic stress disorder (PTSD). Retrieved July 11, 2008 from Mayo Clinic Web site: http://www.mayoclinic.com/health/post-traumatic-stress-disorder/DS00246

(5) National Center for PTSD. (2006, December 12). Facts about PTSD. Retrieved July 9, 2008 from Psych Central Web site: http://psychcentral.com/lib/2006/facts-about-ptsd/

(6) Anxiety Disorder Association of America. (2005). Posttraumatic Stress Disorder (PTSD). Retrieved April 29, 2005 from Anxiety Disorder Association of America Web site: http://www.adaa.org/AnxietyDisorderInfor/PTSD.cfm

(7) Science Daily. (2008, June 13). One in Eight Lower Manhattan residents Had Signs of PTSD Two to Three Years After 9/11. Retrieved June 16, 2008 from Science Daily Web site: http://www.sciencedaily.com/releases/2008/06/080613101105.htm

(8) Anxiety Disorder Association of America. op. cit.

(9) Nauert, Rick. (2007, May 17). PTSD Among New Orleans Residents. Retrieved July 1, 2008 from Psych Central Web site: http://psychcentral.com/news/2007/05/17/ptsd-among-new-orleans-residents/834.html

(10) Price, Jennifer L. (1988). Findings from the National Vietnam Veterans’ Readjustment Study. Retrieved from The United States Department of Veterans Affairs Web site: http://www.ncptsd.va.gov/ncmain/ncdocs/fact_shts/fs_nvvrs.html?opm=1&rr=rr45&srt=d&echorr=true

(11) Tanielian, Terri; Jaycox, Lisa. (2008, April 17). One in Five Iraq and Afghanistan Veterans Suffer from PTSD or Major Depression. Retrieved July 13, 2008 from Rand Corporation Web site: http://www.rand.org/news/press/2008/04/17/

(12) National Center for PTSD. (2006, December 12). Types of PTSD. Retrieved July 11, 2008 from Psych Central Web site: http://psychcentral.com/lib/2006/types-of-ptsd/

(13) Cohen, Harold. (2006, April 8). Differential Diagnosis of PTSD Symptoms. Retrieved July 11, 2008 from Psych Central Web site: http://psychcentral.com/lib/2006/differential-diagnosis-of-ptsd-symptoms/

(14) Stoppler, Melissa Conrad. (2008). Posttraumatic Stress Disorder (PTSD). Retrieved July 11, 2008 from MedicineNet Web site: http://www.medicinenet.com/posttraumatic_stress_disorder/article.htm

(15) Cohen, Harold. (2006, April 8). Frequently Asked Questions about PTSD. Retrieved July 9, 2008 from Psych Central Web site: http://psychcentral.com/lib/2006/frequently-asked-questions-about-ptsd/

(16) Diagnostic and Statistical Manual of Mental Disorders, op. cit.

(17) Cohen, Harold. (2006, April 8). Associated Conditions of PTSD. Retrieved July 11, 2008 from Psych Central Web site: http://psychcentral.com/lib/2006/associated-conditions-of-ptsd/

(18) Cohen. Associated Conditions of PTSD. op. cit.

(19) Price. op. cit.

(20) Nauert, Rick. (2007, September 4). PTSD May Affect Health of Offspring. Retrieved July 1, 2008 from Psych Central Web site: http://psychcentral.com/news/2007/09/04/ptsd-may-affect-health-of-offspring/1224.html

(21) Price. op. cit.

(22) Cohen. Associated Conditions of PTSD. op. cit.

(23) Science Daily. Post-traumatic Stress Disorder is a Medical Warning Sign for Long-term Health Problems, Study Suggests. Retrieved July 11, 2008 from Science Daily Web site: http://www.sciencedaily.com/releases/2008/02/080213090510.htm

(24) Science Daily. op. cit.

(25) Mayo Clinic Staff. op. cit.

(26) National Institute of Mental Health. op. cit.

(27) Diagnostic and Statistical Manual of Mental Disorders. op. cit.

(28) Diagnostic and Statistical Manual of Mental Disorders. op. cit.

(29) National Center for PTSD. Facts about PTSD. op. cit.

(30) Mayo Clinic Staff. op. cit.

(31) Yehuda, Rachel. (2004, November 2). Clinical Relevance of Biologic Findings in PTSD. Retrieved July 17, 2008 from SpringerLink Web site: http://www.springerlink.com/content/c02xtt5a3chprjxq/

(32) Price. op. cit.

(33) True, W.R. et al. (1993, April). A twin study of genetic and environmental contributions to liability for posttraumatic stress symptoms. Retrieved July 17, 2008 from NCBI PubMed Web site: http://www.ncbi.nlm.nih.gov/pubmed/8466386

(34) Nauert. PTSD May Affect Health of Offspring. op. cit.

(35) Nauert, Rick. (2007, May 23). Predisposed to PTSD. Retrieved July 1, 2008 from Psych Central Web site: http://psychcentral.com/news/2007/05/23/predisposed-to-ptsd/845.html

(36) National Center for PTSD. (2006, December 12). Treatment of PTSD. Retrieved July 11, 2008 from Psych Central Web site: http://psychcentral.com/lib/2006/treatment-of-ptsd?

Last updated: December 24, 2008