Section Contents

1. What is PTSD?
2. What is TBI?
3. Relationship between PTSD and TBI
4. Risk Factors for PTSD

1.   What is PTSD?

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), the publication that defines the criteria used in diagnosing mental disorder, classifies PTSD as an anxiety disorder that arises from “exposure to a traumatic event that involved actual or threatened death or serious injury” (American Psychiatric Association 1994).

A.   Symptoms

Symptoms vary considerably from person to person, but the essential features of PTSD include the following (description based on Helpguide 2008):

• Re-experiencing: The most disruptive symptoms of PTSD involve flashbacks, nightmares, and intrusive memories of the traumatic event. The veteran may be flooded with horrifying images, sounds, and recollections of what happened. He or she may even feel like it is happening again. These symptoms are sometimes referred to as intrusions, since memories of the past intrude on the present. These symptoms can appear at any time, sometimes seemingly out of the blue. At other times, something triggers a memory of the original traumatic event: a noise, an image, certain words, or a smell.
• Avoidance/Numbing: Patients with PTSD may attempt to avoid thoughts or activities that could remind them of the traumatic event. In addition, they may lose their ability to experience pleasure and may seem emotionally “flat” or nonresponsive. They may feel detached or estranged from others. Often, they have a sense of a “foreshortened future” feeling that tomorrow may never exist.
• Hyperarousal/Hypervigilance: Individuals with PTSD may feel and react as if they are constantly in danger. This increased arousal may disrupt sleep, contribute to irritability and anger, and impair concentration. Hypervigilance may coexist with an exaggerated startle response.

B.   The Science

PTSD has a biological basis. It is associated with a host of chemical changes in the body’s hormonal system, immune system, and autonomic nervous system. Medical research suggests that the intense bursts of brain activity during traumatic experiences may lay down new neural pathways in the brain (Johnson 2005).

Individuals respond to traumatic experiences along a continuum. Most people have a sudden increased arousal and vigilance. This is a “normal stress response” to danger and generally dissipates with time. For some, the symptoms intensify, become chronic, and interfere with their ability to function (Davidson et al. 2004).

The challenge for mental health professionals and the veterans themselves is to recognize the difference between what has been termed “a normal response to abnormal circumstances” and PTSD. While it is important to avoid “pathologizing” normal reactions, it is equally important to identify when these normal stress reactions are likely to lead to functional limitations. Early intervention will reduce the chance that the stress reaction will become chronic PTSD. In addition, if treatment is delayed, veterans may develop unhealthy coping strategies and may damage their relationships and social support network, leaving them very isolated (Hirsel 2007).

The timing of the onset of stress symptoms varies. These symptoms tend to be heightened by events that elicit memories of the trauma such as anniversary dates or noteworthy "time anchors;” media exposure to war zone events; sights, sounds, or smells that are suggestive of the warzone; certain melodies or lyrics; experiences involving significant losses (such as death of a loved one, etc.); or conflicts with authority (Scurfield 2006).

Some will feel the effects of the trauma while they are still deployed. This is referred to as a combat stress reaction (CSR). Reports from a survey of deployed army revealed that a substantial number of military personnel were experiencing emotional problems during their service in Iraq. For example, 15 percent of those surveyed screened positive for acute stress symptoms and 18 percent screened positive on a combined measure of acute stress, depression, or anxiety. Others may have symptoms immediately upon return from combat, while others may experience a delay of six months to many years, or when they leave the military troops (US Army Surgeon General 2008).

In response to concerns that claims of delayed onset PTSD are attempts to unfairly receive disability compensation, The Institute of Medicine, at the request of the Veterans Benefit Administration, conducted a comprehensive review of the scientific literature and concluded that “considerable evidence suggests that rates of PTSD increase over time following deployment.” (Institute of Medicine and National Research Council 2007)

C.   Comorbidity

PTSD usually occurs in conjunction with other psychiatric, behavioral and medical conditions. Several studies have found that more than 80 percent of people who have been diagnosed with PTSD also have a generalized anxiety disorder, social anxiety disorder, major depressive disorder, or one of a range of psychiatric or substance-related conditions. (Institute of Medicine and National Research Council 2007). The conditions may be triggered by PTSD (e.g., many people turn to alcohol and drugs in an attempt to self-medicate the symptoms of PTSD), or preexisting disorders may increase the risk of PTSD.

A growing body of research is finding a link between PTSD and poor physical health. People with PTSD have more adverse health outcomes in a number of domains such as self-reported health, morbidity, health care utilization, and mortality (Institute of Medicine and National Research Council 2007). Although the psycho-biological mechanism that causes these adverse general medical health outcomes is not well understood, the evidence of the relationship is overwhelming. For example, researchers have found that compared to veterans without PTSD, those with PTSD have substantially higher post-war rates for many chronic conditions including circulatory, nervous system, digestive, musculoskeletal, and respiratory, even after controlling for the major risk factors for these conditions. (Barrett et al. 2002). They also have found shorter average life spans (Boscarino 2005).

D.   Functional Difficulties

PTSD can affect an individual’s ability to maintain relationships, work, and in some cases, interact with their environment and those around them.

Relationships: Research with Vietnam veterans clearly documents the adverse effects of PTSD on intimate relationships. Vietnam veterans with PTSD are twice as likely as veterans without PTSD to have been divorced and three times as likely to experience multiple divorces. Veterans with PTSD perpetrate domestic violence at greater rates than comparable veterans without PTSD. (American Psychological Association 2007).

Although many couples are able to withstand the stress of PTSD, some military spouses, in their blogs, describe a similar dynamic. The veteran gets anxious and angry over little things, making everyday life for the family incredibly stressful. Compounding the everyday stress, the veteran may feel emotionally numb and “put up a wall,” becoming uninterested in social and sexual activities. The spouse, hurt and stressed, may “snap” at the veteran and the anger escalates as the cycle continues. In other situations, the veteran with PTSD may have a sharp temper or violent streak that scares or angers the spouse. 

Work: A diagnosis of war-related PTSD has been linked consistently to poor employment outcomes (Smith et al. 2005). Many symptoms of PTSD can directly affect job performance, such as difficulty concentrating on job tasks, handling stress, working with others, taking instructions from a supervisor, or maintaining reliable attendance.

Interacting with the environment: For people with PTSD, memories may be triggered by sights, sounds, smells, or feelings that remind them of the traumatic event. This reaction may cause them to become isolated.

E.   Comorbidity

According to current estimates, between 10 and 30 percent of service members develop PTSD within a year of combat. When one considers a range of mental health issues including depression, generalized anxiety disorder, and substance abuse, the number increases to between 16 and 49 percent (Hoge et al 2004, Milliken et al 2007, Tanielian and Jaycox 2008, US DoD Task Force on Mental Health 2007, Army Surgeon General 2008).

The precise prevalence of PTSD among service members who have returned from deployment to Iraq and Afghanistan cannot be determined at this time. The estimates of probable PTSD are affected by a number of factors including the sensitivity and specificity of the screening instruments used in the study; the time period after combat when the questionnaire or assessment is administered; and response bias among service members who may be reluctant to acknowledge symptoms due to factors such as stigma or fear of impact on their career.

Although estimates vary, all conclude that a significant number of service members and veterans are at risk for various degrees of stress reaction, including for some diagnosable PTSD.

2.   What is TBI?

Traumatic brain injury (TBI), also called acquired brain injury or simply head injury, occurs when a sudden trauma causes damage to the brain. TBI can result when the head suddenly and violently hits an object, or when an object pierces the skull and enters brain tissue.

A.   Symptoms

Symptoms of TBI can be mild, moderate, or severe, depending on the extent of the damage to the brain. The term “mild TBI” is synonymous with “concussion.” (Hoge et al 2008). A person with a mild TBI may remain conscious or may experience a loss of consciousness for a few seconds or minutes. Other symptoms of mild TBI include headache, confusion, lightheadedness, dizziness, blurred vision or tired eyes, ringing in the ears, bad taste in the mouth, fatigue or lethargy, a change in sleep patterns, behavioral or mood changes, and trouble with memory, concentration, attention, or thinking. A person with a moderate or severe TBI may show these same symptoms, but may also have a headache that gets worse or does not go away, repeated vomiting or nausea, convulsions or seizures, an inability to awaken from sleep, dilation of one or both pupils, slurred speech, weakness or numbness in the extremities, loss of coordination, and increased confusion, restlessness, or agitation (National Institute of Neurological Disorders and Stroke 2008).

Most brain injuries are mild, and many soldiers with mild TBI can recover with rest and time away from the battlefield. However, the military estimates that one-fifth of the troops with these mild injuries will have prolonged—even lifelong—symptoms requiring continuing care (US Army Surgeon General 2008). They may have cognitive issues such as difficulty thinking, memory problems, attention deficits, mood swings, frustrations, headaches, fatigue, or many other symptoms.

B.   Prevalence

VA only recently began a widespread TBI screening program and DoD has only recently begun documenting TBIs in each service member’s medical record. As a result, neither DoD nor VA can estimate the prevalence of TBIs based on screenings. Based on available survey data, an estimated 11 to 20 percent of service members sustained a mild TBI/concussion while serving in OEF/OIF (US Army Surgeon General 2008, Hoge et al. 2008, Taneilian and Jaycox 2008).

3.   Relationship Between PTSD and TBI

PTSD and TBI are often addressed together for two reasons. First, the symptoms may be similar, so it is difficult to distinguish between the two injuries. Second, many people with TBI also have PTSD.

Although PTSD is a biological/psychological injury and TBI is a neurological trauma, the symptoms of the two injuries have some parallel features. In both injuries, the symptoms may show up months after someone has returned from war, and in both injuries, the veteran may “self medicate” and present as someone with a substance abuse problem. Overlapping symptoms include sleep disturbances, irritability, physical restlessness, difficulty concentrating, and some memory disturbances. While there are similarities, there are also significant differences. For example, with PTSD individuals may have trouble remembering the traumatic event, but otherwise their memory and ability to learn is intact. With TBI the individual has preserved older memories, but may have difficulty retaining new memories and new learning.

Research indicates that people with TBI are more likely to develop PTSD than those who have not incurred a brain injury (Hoge 2008). Two scientific theories attempt to explain this relationship. First, TBI can damage a person’s cognitive function and hinder their ability to manage the consequences of his or her psychological trauma, thus leading to a greater incidence of PTSD (Bryant 2008). Second, a mild TBI injury in the combat environment, particularly when associated with loss of consciousness, reflects exposure to a very intense traumatic event that threatens loss of life and significantly increases the risk of PTSD (Hoge 2008).

4.   Risk Factors for PTSD

Several factors have been shown to increase the risk of PTSD. Some of these factors are particularly common to the deployments in Iraq and Afghanistan, which may account for the high rate of injury among service members and veterans.

A.   Characteristics of Deployment

• Length of deployment—Numerous studies document a direct relationship between the amount of exposure to combat stressors and the likelihood of eventually developing PTSD (Scurfield 2006).
• Multiple deployments—Confirming that the amount of exposure increases risk, the MHAT-V found that soldiers have an increased risk with each additional deployment; 27 percent of soldiers on their third deployment reported serious combat stress or depression symptoms, compared to 19 percent on their second, and 12 percent on their first deployment (US Army Surgeon General 2008).
• Violation of expectations—When deployment length is longer than expected (such as when the length of deployment changes in the middle of the deployment) the rate of PTSD increases (Rona et al. 2007).
• Sleep deprivation—Soldiers who report being sleep deprived are at significant risk of reporting mental health issues. It is unclear whether sleep deprivation is a symptom or the cause of mental health issues. In MHAT-V soldiers reported an average of 5.6 hours of sleep, which is significantly less than what is needed to maintain optimal performance (US Army Surgeon General 2008).
• Inadequate dwell time—The dwell time, (the time between the end of one deployment and a redeployment) has an important impact on PTSD (Hoge 2008) The optimal minimum dwell time for active duty military is twice the period of the initial deployment (a 1:2 deployment to dwell ratio) and a 1:5 deployment to dwell ratio for National Guard and Reserve troops. (Defense Science Board 2007). Thus, a service member deployed for a year should have at least two years dwell time before being redeployed. Many of the adaptive skills necessary in combat must be "turned off" when service members come home and "turned back on" when they return for their next deployment. Evidence suggests that 12 months is insufficient time to “reset” the mental health of soldiers after a combat tour of over a year (US Army Surgeon General 2008).
• Types of combat exposure—Certain “malignant” types of combat exposure also appear to place service members at particular risk. For example, McCarroll et al. (1995) found higher levels of PTSD symptoms in veterans who had handled human remains compared to those who had not.
• Training—Service members who feel unprepared for their work in theater and those who perceive the events as unpredictable are more likely to develop PTSD (Iverson 2008). Stress-exposure training, which involves simulations of dealing with dead noncombatants, unconventional combatants, injuries, surprise attacks, and live-fire actions, can help prevent combat stress reactions in theater by preparing service members in advance for situations they may face in combat (Hosek 2006).
• Bodily Injury—Soldiers who sustain bodily injury are more likely to develop PTSD than are soldiers who experienced the same event but were not physically injured (Koren et al. 2005).
• Military Sexual Assault—Being sexually assaulted while in military services leads to PTSD in some, generally female, veterans. There is evidence that military sexual assault makes PTSD more likely than does sexual assault occurring before or after military service (Yeager et al. 2006).
• Unit Cohesion—Many researchers have found that strong unit cohesion and leadership reduces the risk of PTSD. High levels of unit cohesion seem to increase the resilience of service members to cope with military-related stressors (Brailey et al. 2007). However, for some, high levels of unit cohesion may be seen later as an illusion that has been betrayed, increasing anger and risk of PTSD (Brailey et al. 2007).

B.   Personal Factors

Service members process what happens in combat in the context of the rest of their lives. As a result, early childhood adversity, previous trauma, and history of mental illnesses increase the risk of PTSD. Low education, ethnic minority status, younger age, and lower rank are also associated with increased risk (Brewin et al. 2000, Riddle et al. 2007, Iverson et al. 2008).

Two post-deployment factors are associated with an increased risk of PTSD: lack of social support and “life stress” (Brewin et al. 2000).