What distinguishes post traumatic stress disorder from other types of stress reactions that people have?

Acute stress disorder

Benzodiazepines

Benzodiazepines are prescribed to treat anxiety, acute stress reactions and panic attacks. Memory loss is a major feature. Psychological dependence on benzodiazepines is common but the effects are considerably less severe than with most other sedatives. Physical dependence can develop fairly quickly – sometimes within 1 month. Withdrawal symptoms are frequently delayed in onset compared with the barbiturates but may last 8–10 days. Typical effects include insomnia, anxiety (which may be incorrectly attributed to the return of the original anxiety state), loss of appetite, tremor, perspiration and perceptual disturbances, and occasionally fits or psychoses. Sudden withdrawal, particularly of short-acting benzodiazepines, is dangerous since it can cause confusion, fits, toxic psychosis or a condition resembling delirium tremens.

Positive posttraumatic life trajectories

“Stress resistance” involves successful coping with acute stress reactions such that the person experiences no more than mild and brief difficulties in work, relationships, and psychological and physical health (represented by the shallow dip in the line during the peritraumatic period during and soon after the traumatic stressor, as shown in the light solid line at the top of Figure 2.2). Stress resistance is common following ordinary life stressors that are upsetting, worrisome, or challenging but neither traumatic nor particularly persistent or burdensome. Stress resistance is less common following traumatic stressors and is most likely to occur:

when the traumatic event is relatively brief and does not involve severe emotional or physical damage or suffering (such as a motor vehicle accident that happens quickly and despite potentially being disastrous actually does not cause any major injuries or the death of anyone involved);

when intentional acts of cruelty or exploitation such as abuse, purposeful violence, or sexual violation are not involved (such as an accidental injury);

when the traumatic event does not cause prolonged adversity in its aftermath (such as a natural disaster in which most people were able to safely survive and keep their homes and community intact);

where the individual did not feel helpless and unable to take steps, either during or soon after the event, to prevent harm from occurring, reduce the severity of harm, or to hasten successful recovery for self and others (such as military combat in which the combatant is able to prevent an ambush from occurring or respond to the attack in ways that prevented severe harm or death from occurring to comrades or other friendly personnel and civilians).

“Resilience” refers to successful coping with acute stress reactions and problems in living following exposure to a traumatic stressor, such that the person adjusts and functions well even if these acute posttraumatic stress reactions are intense. The person who is resilient in the wake of psychological trauma may be terrified, shocked, confused, grief stricken, or even horrified by the events and their aftermath, but she or he is able to regain emotional and mental balance and focus over the subsequent days such that PTSD does not develop or is at most a relatively temporary condition.

“Recovery” involves suffering PTSD or other severe posttraumatic problems and then later regaining healthy functioning. Psychological, psychiatric, or social interventions have been designed specifically to help people recover from PTSD (see Chapters 7 and 8Chapter 7Chapter 8). However, many people who do not receive special treatment or assistance are able to recover from PTSD for reasons that are not fully understood. Several theories have been advanced to explain how psychosocial resources such as innate resilience or intelligence, supportive relationships, and economic and social “capital” may lead some persons (and communities) to recover from posttraumatic impairment without receiving formal treatment for PTSD (see Chapter 9). As noted earlier in this chapter, as many as 80% of people who receive an evidence-based CBT for ASD (and 25% of those who do not receive this targeted therapy) do not develop PTSD and therefore can be considered to be “early recovers.”

“PTG” is a fourth positive trajectory that is less common (or possibly more common than suspected, but often unrecognized, because growth is not typically expected to occur in the wake of traumatic experiences). PTG involves the development of new knowledge, abilities, relationships, or hope and confidence following a traumatic stressor in addition to recovering successfully from acute stress reactions. For example, people whose homes and communities are devastated by disasters such as hurricanes, cyclones, tornados, or earthquakes at times are able to not only rebuild or relocate successfully but also to develop a keen appreciation for their relationships, work, personal activities, or spiritual faith that is beyond what they had experienced prior to the traumatic disaster. Whether or not this is personal growth due specifically to the traumatic stressor that they experienced remains controversial (see Box 2.4), but their sense of having grown often is very strong and is associated with resistance, resilience, and recovery from PTSD.

Box 2.4

PTG: Can Traumatic Stressors Produce Personal Growth?

For many years, survivors of psychological trauma have described feeling a sense of psychological, emotional, or spiritual growth as a result of enduring and overcoming adversities such as war, genocide, family violence, child abuse, and life-threatening accidents, disasters, or illnesses. Trauma survivors have described feeling as if they have been given a second chance and as a result have a keener appreciation of the opportunities that they have in their lives and relationships. Experiences that previously seemed mundane or went unnoticed in the rush to meet deadlines and follow habitual routines might seem to have a new significance. The survivor might feel able, or even inwardly compelled, to “stop and smell the roses”—that is, to mindfully pay attention to and find value in every experience. Some say that they feel a sense of clarity of vision and purpose, or a revised set of priorities, where they had been stagnating or living reflexively before (Salter & Stallard, 2004). A classic example is Dr. Viktor Frankl’s (1946) observations of spiritual and existential inspiration during the Holocaust in Nazi concentration camps. Clinicians working with survivors of psychological trauma have been deeply affected by similar personal stories of personal and spiritual renewal in the face of trauma, leading to a challenge to the dominant pathologizing view of psychological trauma (that traumatic stress damages the body, mind, and relationships): perhaps experiencing traumatic stressors can lead to personal PTG (Joseph & Linley, 2008; Tedeschi & Calhoun, 2004).

Research on PTG has resulted in factor analyses of the data from a number of self-report questionnaires that have been developed to assess PTG (see Joseph & Linley, 2008). These studies have yielded a primary (“higher order”) factor reflecting a wide range of positive changes following exposure to stressors or psychological trauma, and three secondary (“lower order”) factors that represent the positive components of posttraumatic adaptation: (i) enhanced relationships, (ii) new beliefs and understanding about oneself, and (iii) change in life philosophy (Joseph & Linley, 2008). Additional analyses of scores from PTG self-report measures suggest that the positive adaptations in the wake of psychological trauma may represent a unique dimension of posttraumatic adjustment that is distinct from negative changes such as PTSD symptoms rather than merely the opposite end of a single positive-negative continuum of posttraumatic adaptation (Joseph & Linley, 2008).

Numerous studies have attempted to measure positive posttraumatic adaptations using PTG questionnaires (e.g., 39 studies reviewed by Joseph & Linley, 2008). However, some important limitations in the methodologies of these studies limits the conclusions that can be drawn about using PTG as the organizing construct for positive posttraumatic adaptation. Three methodological issues are of particular concern (Ford, Tennen, & Albert, 2008). First, each measure of PTG has different questions and response formats and requirements, so it is difficult to compare results across studies. Second, PTG almost always is assessed by self-report, which means that what is being studied is the survivor’s subjective view rather than more objective evidence of actual personal growth. Third, there are few studies that measure PTG at several periods over time (“longitudinal” studies; see Research entry, this volume) and that include measures of the individual’s pretraumatic event status in the areas of purported “growth.”

Concerning the measurement of PTG, most (27/39) of the studies reviewed by Linley and Joseph (2004) did not use well-validated measures of PTG. In addition, of the seven published instruments that were used to measure PTG in those studies, only two—the Changes in Outlook Questionnaire and the Revised Stress-Related Growth Scale—inquire about negative as well as positive change (Joseph & Linley, 2008). Thus, respondents may overreport positive changes simply because they are only asked about positive change. On the encouraging side, broadening the field of measurement to include positive as well as the more often assessed negative sequelae of traumatic experiences is an important advance in the traumatic stress field. However, assessment tools for PTG should be designed either to include or to be copresented with other measures of negative changes, and to assess threats to validity such as is done with the “validity scales” that are used in many psychological questionnaires (Ford et al., 2008).

PTG questionnaires also do not differentiate between positive states or outcomes that are an extension or continuation of prior psychological growth or development, versus changes that represent the qualitatively distinct discontinuities in the person’s development that are necessary in order to demonstrate that the PTG is actually related to experiencing trauma (Ford et al., 2008). Frazier and Kaler (2006) note that retrospective self-report measures of PTG are vulnerable to error because of the well-documented difficulty that people have inaccuracy recalling past states or attributes, making it unlikely that they can accurately compare current states or attributes to past ones when estimating the nature or extent of “growth.” PTG measures also do not rule out alternative explanations for outcomes that are supposedly the product of exposure to psychological trauma: for example, growth following psychological trauma may be due to survivors receiving unusual amounts of social support from family, friends, community, or professional helpers, or to the opportunity (born of necessity) to temporarily suspend their usual life routines and responsibilities in the aftermath of psychological trauma (Ford et al., 2008). Thus, growth that seems to be a response to psychological trauma actually may be due to other associated changes that are at most indirectly related to experiencing trauma per se.

People also may be influenced by wishful thinking and denial, particularly in the wake of stressful events (Frazier & Kaler, 2006). McFarland and Alvaro (2000) found that psychological trauma survivors tended to rate their preevent functioning less favorably than did other observers, and therefore rated their postevent functioning as more improved simply because they viewed themselves in a less favorable light before the traumatic event. Smith and Cook (2004) suggest that this downplaying of strengths prior to psychological trauma and the corresponding increase in estimates of the positive change experienced in the wake of traumatic events may be an example of the concept of a “positive illusion.” Such an illusion—the belief that PTG has occurred when there may be very little actual change—could help survivors cope with the negative impact of psychological trauma. Specifically, altering one’s self-perceptions might increase a sense of control following a traumatic event. This could be a positive posttraumatic adaptation, but it might not reflect “growth” and might provide an increase in self-efficacy that could be transient and vulnerable to breaking down if negative posttraumatic changes become pronounced or if further stressors are encountered in the recovery period (Ford et al., 2008).

Some descriptions of positive outcomes following exposure to psychological trauma may reflect survivors’ relief rather than growth. For instance, Salter and Stallard (2004) interpreted statements by children who had experienced a traumatic accident such that they felt “lucky” to be alive or that, “Anything you want, go for it quicker as you never realize when you are going to go.” These statements may reflect an attempt to cope with the heightened realization of mortality that is a hallmark symptom of PTSD (i.e., sense of foreshortened future; Ford et al., 2008). This attitude also may reflect a personality trait that Rabe, Zollner, Maercker and Karl (2006) describe as “goal-related approach tendencies” (p. 883). In a study with survivors of life-threatening motor vehicle accidents on average 5 years later, Rabe et al. (2006) found that scores on the Posttraumatic Growth Inventory (PTGI) subscales that represented a tendency to seek control and find meaning were associated with patterns of activation the brain that are likely to be related to an enduring trait of setting goals and seeking personal control and meaning. Thus, Rabe et al.’ (2006) findings suggest that “growth” may be a preexisting trait and not a posttraumatic change—an adaptation based primarily on preexisting capacities rather than a response caused by the experience of psychological trauma per se.

The ultimate evidence of growth following exposure to psychological trauma would come from studies in which people who experience psychological trauma had already been assessed prior to experiencing traumatic events (see Longitudinal Research studies section, this chapter). The optimal scenario would include a series of assessments over a period of months or years prior to trauma exposure, rather than no pretrauma baseline or only a single measurement of pretrauma status. This is an ambitious approach that has not yet been reported in the published research on psychological trauma. It would provide evidence of not only their pretrauma status at one time-point but whether there already was evidence of “growth” (or stability, or a decline) along potential pathways or trajectories of posttraumatic adaptation that include the many areas of psychological functioning that are assessed following the traumatic event(s). Then it would be possible to test survivors again using the same or similar measures over a period of time following the traumatic event(s) in order to determine if there is evidence of change and if there is an increase in the rate of positive change following the traumatic events compared to their rate of change prior to trauma exposure. No such studies have as yet been reported.

Linley and Joseph (2004) identified three longitudinal studies of PTG, but none of them measured preevent functioning. Two other longitudinal studies have included pretrauma baseline measures, however. Davis, Nolen-Hoeksema, and Larson (1998) assessed bereaved adults during a hospice program on average 3 months prior to a loved one’s death, and then for the next 18 months. Controlling for preloss distress levels, they found that making sense of the loss was associated with less distress in the first year postloss, and reporting benefiting from the experience was associated with less distress more than a year after the loss. However, it is not clear that the “preloss” distress levels were a true baseline because the loss was imminent and the stress of caregiving often already was protracted at the time of the baseline assessment (Ford et al., 2008). It also is not clear that the “benefit” was associated with loss per se, as opposed to other factors such as social support or preexisting resilience (Ford et al., 2008).

In the second longitudinal study with a pretrauma baseline, Ickovics et al. (2006) obtained an assessment of psychological distress from inner-city adolescent girls who were sexually active (half of whom were pregnant), and reinterviewed them every 6 months, for a total of 18 months. Trauma history and PTG were assessed at the 12-month assessment by open-ended responses to a question asking about the “hardest thing [they] ever had to deal with” and by the PTGI subscales reflecting a tendency to seek positive experiences in life. Controlling for baseline distress levels, PTGI at 12 months predicted reduced emotional distress 6 months later. However, the traumatic events may have occurred at any point in the girls’ lives, so there actually was no pretrauma baseline. Stability or change in PTGI was not assessed, nor were other factors such as stable personality traits and social support. Therefore, the PTG’s apparent relationship to emotional distress 6 months later may be due to many factors, and whether the PTGI scores actually reflected growth due to traumatic adversity is unknown.

Overall, methodological weaknesses in these studies makes any conclusions premature with regard to whether PTG actually occurs, what factors increase or decrease the likelihood of PTG, how PTG occurs psychologically and neurobiologically, and what temporary or lasting benefits are associated with PTG. Nevertheless, PTG remains a plausible form of posttraumatic adaptation, given the abundance of testimonials of PTG in popular culture and by clinicians who work with psychological trauma survivors, and the many studies attempting to measure PTG. As Ford et al. (2008) summarize, growth may occur as a result of overcoming adversity, but the evidence is not conclusive as to whether “ PTG” constitutes (i) actual sustained growth; (ii) temporary changes in mood, expectancies, and lifestyle; (iii) reappraisals to compensate for distress (e.g., positive illusions); (iv) the restoration of prior capacities following an adaptive shift from ordinary to survival-based self-regulation (i.e., resilience); or (v) measurement artifact.

Whether positive reinterpretation and acceptance coping are manifestations of actual growth, and not enduring personality traits, and change that has been catalyzed by experiencing traumatic stressors (as opposed to transient attempts to maintain emotional balance and hope in the wake of psychological trauma), remains unknown. The fact that some psychological trauma survivors feel that they have been given a second chance or a new lease on life, and in some cases are able to parlay this sense of relief and renewal into positive adaptations in their lives and relationships, is undeniable and serves as an inspiring reminder of the remarkable resilience that has made possible some of humanity’s greatest accomplishments despite—and perhaps in part due to—the adversities of psychological trauma.

Assessment for Screening

The objective of screening is to identify individuals exposed to traumatic events who are at risk for developing acute stress disorder or PTSD and require further evaluation for differential diagnosis and treatment planning. Psychological distress is a normal reaction to a traumatic event for the majority of individuals who suffer or witness it. The purpose of screening is to distinguish individuals who will likely have only transient distress from those who may require additional evaluation to rule out PTSD and other stress-related mental, substance use, and neurological disorders.

The majority of patients with stress-related conditions present to primary care providers complaining of somatic and psychological symptoms, such as sleep disturbance, fatigue, depression, anxiety, and problems with concentration. To screen for individuals at risk for PTSD, practitioners can use the Primary Care PTSD Screen and the PTSD Checklist, validated screening tools available from the National Center for PTSD.

Short-Term Stress Effects

The explosion in the NPP contained stressful stimuli typical of shock trauma. This is likely to produce acute stress reactions and later posttraumatic stress disorder (PTSD, a psychiatric disorder characterized by intrusive recollections and the reliving of the trauma, along with symptoms of avoidance and hyperarousal. Unlike the stimuli carrying a high risk of PTSD, which were time-limited dangers, additional stressors inherent in the radioactive contamination were ongoing, future oriented, somatically based, and not confined to a single past event that could be processed by the senses.

The Chernobyl NPP accident started a sequence of events that has continued to unfold over several years, thereby creating a situation of chronic stress. For the people exposed, the Chernobyl nuclear accident had no clearly defined low point from which things would gradually get better. Exposures to a high-risk environment, even when the feared consequences, such as cancer, may never materialize, elicit stress reactions that are influences by individual perceptions of the danger. The fear was aggravated by the lack of adequate information immediately after the accident.

Human contamination of the biosphere is a comparatively new type of crisis. Rather than merely an ecological and medical emergency, this was also a social and political crisis. In the affected regions, covering thousands of square kilometers, a culture of uncertainty developed. The environmental contamination was not possible to see, hear, smell, taste, or touch. In a silent disaster, it is impossible for humans to determine if and when they are being exposed because they are totally dependent on experts for information. Because of the secretiveness of the Soviet authorities, news about the accident was released several days after the accident. Only then did the populations in nearby towns become aware of the radiation to which they had been exposed and the consequent threat of long-term illness. These people were struck by fear and the distrust of political authorities. When people were evacuated from their homes, they suffered considerable stress because they were kept ignorant about what was going on. They underwent disruption in community infrastructure and social interaction and faced uncertainty about future housing and employment. Many evacuees who moved to new settlements were particularly depressed in their new homes because of financial difficulties, fear of isolation, and concern for the health of their children. The tense situation caused considerable stress, which, combined with the constant fear of health damage from the radioactive fallout, led to a rising number of health disorders being reported to local outpatient clinics. People received late and reluctant information, leading to widespread rumors. Only 30 months after the accident did Soviet authorities admit the contamination of some villages. This obvious disinformation resulted in widespread indifference, denial of danger, and public distrust in the government. People suffered from various symptoms frequently called chronic radiation sickness, the exact definition of which varied; fatigue, loss of memory, loss of appetite, and psychosomatic symptoms were among the most frequently documented symptoms in the clinics.

The findings of increased somatic complaints, with large discrepancies between the findings of thorough clinical examinations and the self-reports is reminiscent of Lifton's psychosomatic bind, found among Hiroshima atomic bomb survivors. Thus, substantial proportions of the populations in the former Soviet Union, severely affected with Chernobyl fallout, live with an intense focus turned inward, listening for all kinds of physical health complaints that might possibly be the first signals confirming their expectations of becoming ill consequent to the impact of Chernobyl.

Similarly, in recent years, several authors have suggested that psychological factors may be involved in the etiology and pathogenesis of the health problems occurring after toxic exposure. A number of terms have been proposed to describe this syndrome: chronic environmental stress syndrome, informed of radioactive contamination syndrome, and toxic stress syndrome.

Predispositions and Precipitants

It should be emphasized that no single factor by itself, even if the stress is tremendous, totally accounts for the development of an acute stress reaction. Rather, it is the sum of separate forces acting in concert over a brief period of time. These forces usually include developmental factors, environmental conditions, and interpersonal stresses.

Developmental factors influencing susceptibility to acute stress response include childhood family traumas, especially abuse and neglect; poor socialization while growing up; low educational attainment; and little success in managing major life stresses (Figure 1). These individuals often join the military to escape from their troubled lives. The last thing they expect, and what their early lives has left them unprepared to handle, is to go into combat.

In contrast, resistance factors to acute stress reaction include enriched childhood and developmental experiences, prior stress experiences that the person handled successfully, high intelligence and educational achievement, plentiful social support, and prior training on how to handle stress (Figure 2). A positive attitude and an ability to resist rash behaviors are traits that enhance resistance to stress.

Environmental stresses, such as fatigue, hunger, sleep loss, cold, and heat, are common experiences of men in battle. They take on additional significance when other precipitants of acute battle stress coexist, for example, when a battle is being waged in sustained heat (such as a desert war) and soldiers are dehydrated. The high magnitude of the stress situation, especially with a high casualty rate, makes stress reactions more likely to occur. A surprise event leading to disorientation, concurrent illness, and poor physical endurance add even further to a susceptibility to acute stress response.

Interpersonal factors also contribute to susceptibility to stress, including recent life stresses outside of combat, such as family upheaval at home, financial problems, and difficulties getting along with peers. Reserve status, rather than a regular commission, and membership in a support unit (usually armor) are frequently an interpersonal precipitant of this disorder. Soldiers, who are members of elite units, in which the esprit de corps and morale are generally quite high, tend to perform far better in combat than men in less cohesive units. A further interpersonal stress occurs when reserves are brought forward to replace the dead and injured. These reserves may be assigned to tanks that are still bloody from the previous campaign and find themselves communicating, by radio, with people they have never met. A replacement soldier is seen as a new guy by the others and is a reminder that one of their buddies was killed or severely wounded. It may take weeks to months for a new soldier in a unit to lose this new guy label.

Factors of older age and inexperience are two additional interpersonal precipitants of this stress response. An infantryman in his late twenties or early thirties has a much higher probability of developing an acute combat reaction than one in his late teens or early twenties. Soldiers are especially vulnerable to acute stress reactions when they witness death for the first time. One of the major functions of military training is to prepare soldiers for the rigors of battle so that they can function almost reflexively in that environment. Yet it is impossible to train men for the experience of seeing their buddies killed.

Acute stress disorder

In light of temporal constraints in the diagnostic criteria of PTSD that preclude a diagnosis within the first month, a second diagnosis was introduced to capture acute stress reactions that occur in the immediate aftermath of a traumatic event (Bryant and Harvey, 2000). Clinicians hoped that such a diagnosis would help them identify individuals at high risk for PTSD for psychiatric care, to deploy early interventions and stave off progression to more persistent symptoms (Bryant et al., 2000; Harvey and Bryant, 2002).

Acute stress disorder (ASD) first appeared in the DSM-IV (American Psychiatric Association, 2000) as a more acute form of PTSD, lasting for at least 2 days and no more than 4 weeks after the traumatic event. ASD is qualitatively very similar to PTSD and includes many of the re-experiencing, avoidance, and arousal criteria from the PTSD diagnosis. However, in addition to the temporal constraints that set ASD apart from PTSD, ASD places a greater emphasis on dissociative symptoms. The diagnosis of ASD requires at least three of the following: (1) subjective sense of numbing or detachment, (2) reduced awareness of surroundings, (3) derealization, (4) depersonalization, or (5) dissociative amnesia (Bryant and Harvey, 1997). The motivation for this distinction is grounded in the theoretical assertion that dissociation is the primary mechanism for coping with the extreme stress in the days and weeks following a traumatic experience (Bryant and Harvey, 1997).

A recent systematic review of ASD suggests that approximately 17% of those who experience an emotionally traumatic event go on to satisfy the diagnostic criteria for ASD, with approximately 26% satisfying at least three of the symptom clusters (Bryant, 2011). Of these individuals, approximately half will subsequently meet the criteria for PTSD. However, ASD is not a sensitive indicator of subsequent PTSD. More than half of trauma survivors who eventually meet the diagnostic criteria for PTSD do not meet the diagnostic criteria for ASD (Bryant, 2011). If dissociative symptoms are ignored, a diagnosis of ASD is significantly more accurate in predicting subsequent PTSD. This suggests that PTSD-like symptoms within the first month after a traumatic experience may be a better predictor of the progression to PTSD than ASD per se (Bryant et al., 2012). Despite the failure of the diagnosis to effectively identify trauma survivors at risk for subsequent PTSD, ASD appears to be particularly good at predicting subsequent PTSD in individuals with a TBI (Harvey and Bryant, 2000, 2002). The implications for ASD following TBI will be discussed in subsequent sections.

1.1 Psychiatric Comorbidity in the General Hospital

It is estimated that between 30 and 50 percent of physically ill patients in general hospitals show comorbid psychiatric disorders, especially organic psychoses (ICD-10 F0), psychological and behavioral disturbances due to psychotropic substances (ICD-10 F1), and acute stress reactions (ICD-10 F4), with percentages of these diagnoses ranging as high as 16 percent, 8 percent and 10 percent in medical, and 17 percent, 8 percent and 13 percent in surgical patients, respectively (Arolt 1997). Special patient populations—such as those in organ transplantation programs, intensive care units, or oncological patients—show an even higher psychiatric comorbidity. The presence of psychiatric comorbidity does not always call for psychological treatment at the same time as the underlying or concomitant physical disease is being treated by physicians or surgeons. Neverthless, conservative estimates point to a figure of some 10 percent of general hospital inpatients who should receive psychiatric care alongside somatic care.

While the evaluation of patients committed to Accident and Emergency Departments after attempting to harm themselves is an important task for psychiatrists, and will often be performed by c-l services, their care is only one part of a larger picture of care for patients suffering from medical and psychiatric comorbidity, with the latter impacting negatively on course and outcome of the former. A prerequisite for psychiatric services to achieve an impact on this group of patients is the integration of psychiatry into general hospitals. Thus, in the USA, where the foundation of psychiatric departments as integrated parts of general hospitals started as early as the 1920s, c-l psychiatry has a long tradition, whereas in the Federal Republic of Germany, for instance, where state mental hospitals have given way to general hospital psychiatric departments only since the end of the 1970s, c-l psychiatry started to gain shape only toward the end of the twentieth century. Overall, international interest in c-l psychiatry increased outside the USA during the 1980s and 1990s with special emphasis in the UK, the Netherlands, Australia and New Zealand, where c-l psychiatric sections exist within national psychiatric organizations. The history of c-l psychiatry shows that the acceptance of psychiatric care for patients with medical–psychiatric comorbidity is dependent largely on the regular availability of psychiatrists in general hospitals, which provides the opportunity to demonstrate the added value of psychiatric diagnosis and treatment to other medical disciplines in the care of comorbid patients.

1.2 Epidemiology

Despite changes in diagnostic criteria used to define PTSD between 1997 and 2013, epidemiological rates have not changed significantly. Currently, the most reliable epidemiological data is based on the Diagnosis and Statistical Manual of Mental Disorder, Fourth Edition (DSM-IV) where lifetime prevalence of at least one traumatic event among U.S. citizens is 60%. Although it is common to have acute stress reactions involving upsetting memories, feeling anxious, or having sleep disturbance just after a traumatic incident, symtoms start to resolve after few days for most people. Although most recover from this acute stress reaction, about 8–15% (Herringa, 2017) go on to develop a persistent PTSD diagnosis. About 3.5% of adult population of U.S have a diagnosis of PTSD during a given year, and 9% of people develop it at some point in their life (Kessler et al., 2005). These figures make PTSD the fifth most prevalent mental disorder in the country. Most people with PTSD develop those symptoms within 3 months after a traumatic event, but there may be even longer delays before symptoms appear. A study of veterans reported that nearly half of the sample reported first reported symptoms after a major psychosocial stressor that happened years after the index traumatic event. The rate of probable PTSD for first responders at the New York World Trade Center site was lowest directly after the attacks—increasing from ranges of 4.8–7.8% before to 7.4–16.5% over the 5–6 year follow-up assessment period. The probable PTSD prevalence 2.5 years after the initial visit was greatest not in trained first-responders, but in clean-up volunteers with estimates of 11.7% and 17.2% respectively (Hamwey et al., 2020).