Post Traumatic Stress Disorder: Psychological Factors, Diagnosis

Psychological Factors

Behavioral Models

Conditioning theory has been helpful in explaining the process through which stimuli that are associated with a traumatic event can alone elicit intense emotional responses in individuals who have PTSD. Cues (i.e., conditioned stimuli) that are present at the time of the trauma (the unconditioned stimulus) become as-sociated with the unconditioned emotional response (fear, help-lessness, or horror). Following the traumatic event, these cues alone can then repeatedly elicit the strong emotional response. For example, a woman who has been raped (unconditioned stimulus) in a dark alley (conditioned stimulus) by a man (condi-tioned stimulus) and has an intense fear response (unconditioned response) may demonstrate a fear response (now the conditioned response) when she sees a dark alley (conditioned stimulus) or is in the presence of a man (conditioned stimulus). Avoidance behaviors develop to decrease anxiety associated with the con-ditioned stimuli. For example, the woman who has been raped may avoid going outside when it is dark and also avoid being in the company of men. Behavioral treatments using exposure prin-ciples require confrontation with the feared situation and may ultimately lead to reduction of anxiety.

Cognitive and Information Processing

Exposure to a severe or unexpected event may result in an in-ability to process and assimilate the experience adequately or to deal effectively with its impact. A period of prolonged, difficult and often incomplete assimilation occurs. The experience is kept alive in active memory, intruding itself into awareness either dur-ing the day or at night. The pain of the unbidden experience is followed by active attempts to avoid reminders of the trauma. These intrusive and avoidance phases often alternate (Horowitz, 1973).

Fear can be considered a cognitive structure with three el-ements: stimulus, response and meaning. To reduce fear, the fear memory must first be activated and then new information pro-vided to modify the fear structure. Cognitive interventions can be used to recognize and change maladaptive cognitions and toreplace interpretations of danger by realistic or safer interpreta-tions, with the ultimate hope that the patient will integrate the new information into the fear structure, leading to a more realis-tic appraisal of the degree of danger.

Genetic–Familial Factors

From the available literature, which is based on male combat veterans, general population surveys and rape-trauma-related PTSD, there is evidence to suggest that anxiety and depression in families is a risk factor for PTSD. A twin study of Vietnam vet-erans concordant and discordant for combat exposure has shown that a significant part of the variance is explained on the basis of genetic factors with respect to all three symptom clusters (i.e., in-trusive, avoidant and hyperarousal symptoms) (True et al., 1993). McLeod and colleagues (2001) examined the role of genetic and environmental influences on the relationship between combat exposure, post traumatic stress disorder symptoms and alcohol use in 4072 male–male twin pairs; the authors found that alcohol problems occur together because of a shared vulnerability that increases risk for both disorders. These findings are most con-sistent with the shared vulnerability hypothesis in which combat exposure, PTSD symptoms and alcohol use are associated be-cause some portion of the genes that influence vulnerability to combat also influence vulnerability to PTSD symptoms and al-cohol consumption. It is important to note, however, that specific unique environmental factors the twins did not share were more important than genetic factors for combat exposure and PTSD symptoms, whereas environmental influences appeared about equally important as genetic influences on alcohol use. Overall, the evidence suggests that psychiatric history, both personal or in family members, increases the likelihood of being exposed to a trauma and of developing PTSD once exposed.

Other Factors

Although systematic research is scant, it may be that individuals exposed to repeated or continuous trauma, particularly of an in-terpersonal nature, may be more likely to develop PTSD. Trauma involving loss of community or support structures is likely to be particularly damaging. Because social support has been held to produce a buffering effect, lack of support might be considered an additional vulnerability factor. Women are at more risk than men for PTSD.

Diagnosis

Assessment and Diagnostic Features

The diagnosis of PTSD is based on a history of exposure to a traumatic stressor, the simultaneous appearance of three different symptom clusters, a minimal duration and the existence of func-tional disturbance. To qualify as traumatic the event must have involved actual or threatened death or serious injury or a threat to the patient or others, and exposure to this event must arouse an intense affective response characterized by fear, helplessness, or horror. In children, disorganized or agitated behavior can be seen in lieu of an intense affective response. Symptomatically, there must be at least one of five possible intrusive-reexperiencing symptoms. These have the quality of obsessive, recurring, intru-sive and distressing recollections either in the form of imagery or thoughts, or in the form of recurrent distressing dreams. Intense psychological distress or physiological reactivity on exposure to either an external reminder or an internal reminder of the traumacan also occur. The flashback experience, or reliving of the event, is less common.

Symptom cluster C in the DSM-IV-TR criteria in actual-ity embodies two somewhat different psychopathologies, namely, phobic avoidance and numbing or withdrawal. The phobic avoid-ance is expressed either in 1) efforts to avoid thoughts and feelings, and conversations associated with the trauma or 2) in efforts to avoid activities places or people that arouse recollec-tions of the trauma; 3) psychogenic amnesia, a more dissocia-tive symptom, is also in this symptom grouping, followed by 4) markedly diminished interest; 5) feeling detached or estranged; 6) having a restricted range of affect; and 7) having a sense of a foreshortened future. At least three of these seven symptoms must be present.

Hyperarousal symptoms, somewhat similar to those of generalized anxiety disorder, are also present in PTSD and at least one of five of the following symptoms is required: difficulty sleeping, irritability or anger, poor concentration, hypervigilance and exaggerated startle response.

With regard to the symptoms as a whole, it is evident that they embody features of different psychiatric disorders, including obsessive–compulsive processes, generalized anxiety disorder, panic attacks, phobic avoidance, dissociation and depression. Fi-nally, it is necessary for symptoms to have lasted at least 1 month and for the disturbance to have caused clinically significant dis-tress or impairment.

Assessment and Differential Diagnosis

PTSD symptoms may overlap with symptoms of a number of other disorders in the DSM-IV. Both PTSD and adjustment dis-order are etiologically related to stress exposure. PTSD may be distinguished from adjustment disorder by assessing whether the traumatic stress meets the severity criteria described earlier. Also, if there are an insufficient number of symptoms to qualify for the diagnosis, this might merit a diagnosis of adjustment disorder.

Specific phobia may arise after traumatic exposure. For ex-ample, after an automobile accident, victims may develop phobic avoidance of traveling, but without the intrusive or hyperarousal symptoms. In such cases, a diagnosis of specific phobia should be given instead of a diagnosis of PTSD.

The criteria set for generalized anxiety disorder include a list of six symptoms of hyperarousal, of which four are com-mon to PTSD: being on edge, poor concentration, irritability and sleep disturbance. PTSD requires the additional symptoms as described earlier, and the worry in PTSD is focused on concerns about reexperiencing the trauma. In contrast, the worry in gener-alized anxiety disorder is about a number of different situations and concerns. However, it is possible for the two conditions to coexist.

In obsessive–compulsive disorder, recurring and intrusive thoughts occur, but the patient recognizes these to be inappropri-ate and unrelated to any particular life experience. Obsessive– compulsive disorder is a common comorbid condition in PTSD and may develop with generalization (e.g., compulsive wash-ing for months after a rape to reduce contamination feelings). It may also develop by activation of an underlying obsessive– compulsive disorder diathesis.

Autonomic hyperarousal is a cardinal part of panic attack, which may indicate a diagnosis of panic disorder. To distinguish between panic disorder and PTSD, the therapist needs to assess whether panic attacks are related to the trauma or reminders of the same (in which case they would be subsumed under a diagnosis ofPTSD) or whether they occur unexpectedly and spontaneously (in which case a diagnosis of panic disorder would be justified).

Depression and PTSD share a significant overlap, in-cluding four of the criterion C cluster symptoms and three of the criterion D cluster symptoms. Thus, an individual who presents with reduced interest, estrangement, numbing, impaired concentration, insomnia, irritability and sense of a foreshortened future may manifest either disorder. PTSD may give rise to de-pression as well, and it is possible for the two conditions to coex-ist. In a few instances, a patient with prior depression may be more vulnerable to developing PTSD. Reexperiencing symptoms are present only in PTSD.

Dissociative disorders also overlap with PTSD. In the early aftermath of serious trauma, the clinical picture may be predominantly one of the dissociative states (see the section on acute stress disorder [ASD]). ASD differs from PTSD in that the symptom pattern occurs within the first few days after exposure to the trauma, lasts no longer than 4 weeks, and is typically ac-companied by prominent dissociative symptoms.

More rarely, PTSD must be distinguished from other dis-orders producing perceptual alterations, such as schizophrenia and other psychotic disorders, delirium, substance use disorders and general medical conditions producing psychosis (e.g., brain tumors).

The differential diagnosis is important but, notwithstand-ing, PTSD is unlikely to occur in isolation. Psychiatric comorbid-ity is the rule rather than the exception, and a number of stud-ies have demonstrated that, in both clinical and epidemiological populations, a wide range of disorders is likely to occur at an increased probability. These include major depressive disorder, all of the anxiety disorders, alcohol and substance use disorders, somatization disorder, and schizophrenia and schizophreniform disorder. A few studies have documented the course of comorbid conditions. Major depressive disorder cooccurs with PTSD, but can take a separate course. Comorbid substance abuse tends to be a consequence rather than a precursor of PTSD.