Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a psychiatric disorder characterized by profound disturbances in cognitive, behavioral, and physiological functioning that occur following exposure to a psychologically traumatic event. According to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR), the diagnosis applies to individuals who develop a constellation of symptoms after experiencing, witnessing, or being confronted with an event involving perceived or threatened loss of life, serious injury, or loss of physical integrity and that evoked fear, helplessness, or horror (e.g., military combat, sexual or physical assault, serious accidents, and major disasters). The symptoms of PTSD are organized under three clusters: (1) reexperiencing (e.g., intrusive thoughts, nightmares, flashbacks, and psychophysiological reactivity to reminders of the trauma), (2) avoidance and emotional numbing (e.g., avoiding stimuli associated with the trauma and inability to experience a full range of emotions), and (3) hyperarousal (e.g., hypervigilance, exaggerated startle response, and sleep disruption). By definition, the symptoms must persist for more than 1 month after the trauma and produce clinically significant distress and/or impairment.

Prevalence and Etiology of Trauma and PTSD

Epidemiological studies have found that 40% to 90% of the general population in the United States experience a traumatic event meeting the PTSD stressor criterion at some point during their lifetime. After trauma exposure, the probability of developing PTSD is estimated to be approximately 10% in the general population, although higher rates (i.e., closer to 25%) have been observed after traumatic events involving violence or life threat such as rape and military combat. Numerous factors contribute to the probability of developing the disorder, with the nature and severity of the event being the most important factor. In addition, psychosocial factors such as a family history of psychiatric illness, childhood trauma or behavior problems, and the presence of psychiatric symptoms prior to the trauma appear to mediate the relationship between trauma exposure and the subsequent development of PTSD. Individual difference factors also play a role. After controlling for trauma exposure, the rate of PTSD in women is approximately twice as high as the rate for men. Research suggests that personality traits such as neuroticism and negative emotionality represent vulnerabilities for the development of the disorder, whereas characteristics such as hardiness function as resilience factors.

Terence M. Keane and David H. Barlow adapted Barlow’s model of anxiety and panic to promote an understanding of the variables involved in the development of PTSD. This conceptual model suggests that bio-logical and psychological vulnerabilities underlie the development of PTSD. When an individual is exposed to a traumatic life event, a true biological and psychological alarm occurs leading to both conditioning of stimuli present at the time of the event and to cognitions that incorporate anxious apprehension of a recurrence of the traumatic event. These emotionally charged stimuli then promote the development of avoidance strategies in order to effectively minimize the experience of aver-sive emotional reactions. The emergence of PTSD is a function of these variables as well as the strength of the social support system of the individual and his or her coping abilities in the aftermath of trauma exposure.

Assessment of PTSD

A comprehensive clinical assessment of PTSD should include administration of structured diagnostic interviews, self-report psychometrics, and an evaluation of trauma across the life span. Several structured interviews are available and the Clinician-Administered PTSD Scale for the DSM-IV and PTSD module of the Structured Clinical Interview for the DSM-IV are standards in the field. Self-report instruments can also assist in diagnosis or provide efficient, low-cost methods for research and screening purposes. Of these, several were constructed specifically for assessing PTSD (e.g., Mississippi Scale for Combat-Related PTSD; PTSD Checklist; PTSD Diagnostic Scale) and others were derived from existing items of major inventories such as the Minnesota Multiphasic Personality Inventory-2 (MMPI-2). Finally, instruments such as the Potential Stressful Events Interview and the Traumatic Stress Schedule can be used to evaluate trauma exposure across the life span. Virtually all of the available diagnostic measures of PTSD possess excellent psychometric properties.

Treatment of PTSD

Treatment for PTSD typically involves the use of psychotherapy, pharmacotherapy, or both. Of the psychotherapies, exposure-based approaches (e.g., systematic desensitization, flooding, prolonged exposure, imaginal and in vivo exposure, and implosive therapy) have received the most attention and empirical support to date. The central element of these techniques involves the gradual exposure of the client to trauma-related cues to desensitize and extinguish problematic emotional and physiological reactions. The therapeutic mechanism has been conceptualized within the framework of classical conditioning: repeated exposure to trauma-related cues (e.g., trauma-related images evoked from memory) in the absence of the feared negative consequences (e.g., the trauma itself) reduces the conditioned fear, anxiety, and avoidance characteristics of PTSD.

A second promising category of empirically validated treatments for PTSD is cognitive restructuring therapies, such as cognitive processing therapy. Based on cognitive therapy principles, this approach is designed to identify and modify dysfunctional trauma-related beliefs and to teach specific behavioral and cognitively based coping skills. The procedure may also involve tasks that include an element of exposure such as writing or describing the trauma to disclose trauma-related cognitions. Controlled studies that directly compare treatments for PTSD provide strong evidence for the efficacy of these cognitive-behavioral therapies.

Pharmacological treatment of PTSD is primarily designed to treat symptom clusters of PTSD, rather than the entire syndrome or any underlying physiological dysregulation. Several classes of antidepressants have been found to be modestly effective, including monoamine oxidase inhibitors and tricyclics, with selective serotonin reuptake inhibitors (SSRIs) having the strongest body of empirical support. The SSRIs are currently the first choice of psychopharmacological treatment for PTSD. Presently, studies are underway to examine the effectiveness of cognitive-behavioral therapies and SSRIs when administered jointly. In addition, trials examining augmentation strategies to assess the efficacy of SSRIs with atypical antipsychotic medication are also underway to determine the relative efficacy of these medications in combination.


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