The use of the diagnosis of posttraumatic stress disorder in litigation has been called "a forensic minefield" (Sparr and Boehnlein, 1990). Since its inclusion in the DSM-III, PTSD has been increasingly utilized over the past decades in both civil and criminal litigation (Slovenko, 1994; Sparr and Boehnlein 1990)--so much so that the provision of PTSD testimony into the legal system has been characterized as "a cottage industry" (Stone, 1993).
Attorneys introduce PTSD arguments into legal cases through the use of expert testimony. A diagnosis of PTSD can provide advantages in litigation. In civil litigation, it creates an assumption of obvious causation. It also carries a legal and moral implication that someone else is responsible for an event so overwhelming that anyone could have developed PTSD as a result. Finally, it provides strong support for arguments regarding damages (Gold, 2003; Gold and Simon, 2001). The stressors alleged to cause PTSD and the class of victims who could suffer PTSD from those stressors have expanded the horizons of tort litigation (Shuman, 2003). Posttraumatic stress disorder is also increasingly used in criminal cases, typically in arguments of justification or mitigation in sentencing. In these circumstances, attorneys argue that anyone exposed to the trauma the defendant suffered might find themselves committing similar crimes under similar circumstances.
Common misconceptions about the nature of trauma and PTSDs are partially responsible for the increased frequency of a PTSD diagnosis in litigation. The terms trauma and stress are routinely used synonymously. All traumatic experiences are stressful. However, not all stress is traumatic. Lawyers, laypeople and clinicians all frequently confuse the popular concept of stress as a synonym for trauma with the medical concept of a specific psychiatric disorder that may occur following exposure to a true traumatic event.Credible Expert Testimony
At times, clinical and forensic psychiatrists ignore the requisite diagnostic criteria and regard as PTSD any emotional disturbance that follows an adverse stressful event. To maintain credibility when providing diagnostic assessments of PTSD in litigation, psychiatrists should be familiar with the definition of this disorder and the types of traumatic stressors that can precipitate it. The DSM-IV defines PTSD as a disorder for which six criteria must be met. These include specific symptoms and a degree of functional impairment.
The most important of these in the context of litigation is Criterion A: a person must have been exposed to a traumatic event or stressor. Criterion A defines a traumatic stressor as consisting of an objective and subjective element. Both elements must be met for an event to constitute an emotional stressor that can cause PTSD. In the objective element, the person must have experienced, witnessed or have been 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. These include such experiences as combat, violent personal assault, terrorist attack, being kidnapped, being diagnosed with a threatening illness and automobile accidents, among others. The subjective element of Criterion A requires that the person's response must have involved intense fear, helplessness or horror.
However, even if both elements of the traumatic exposure are present, not every traumatic event causes PTSD in every individual exposed to that event. Epidemiological studies suggest that only 15% to 24% of adults exposed to Criterion A trauma develop PTSD (Breslau, 2001). The risk of developing PTSD also varies by type of trauma and stressor intensity or magnitude. Specific risk factors associated with victim characteristics, such as gender, age, race, socioeconomic class, family dysfunction, comorbid psychopathology or a history of psychopathology, and a previous history of trauma, are also associated with the likelihood of developing PTSD following trauma exposure (Breslau, 2001, 1998; Breslau et al., 1999, 1991; Briere, 1997; Green and Kaltman, 2003).
Epidemiological statistics and identification of risk factors for the development of PTSD should not be used to discount the inherently traumatic nature of many events. Regardless of pre-existing vulnerabilities, PTSD can occur in those without significant risk factors in the face of a high magnitude or intensity traumatic exposure. A previously well-functioning adult can experience a sharp deterioration in functioning after exposure to severe trauma (van der Kolk et al., 1996). However, an examiner should not assume that any traumatic stressor, much less a stressful situation that does not meet Criterion A, will necessarily produce PTSD.
It is possible for individuals to develop PTSD without meeting the stressor criterion. For example, exposure to multiple events appears to increase the risk for the development of PTSD, even if the last stressor does not meet all the elements of Criterion A. Similarly, individuals may be diagnosed with subthreshold PTSD after exposure to a traumatic event if they do not meet the DSM-IV requisite number of symptoms for a formal diagnosis of PTSD (Blank, 1993; Schutzwohl and Maercker, 1999; Stein et al., 1997; Weiss et al., 1992). Nevertheless, unless the stressor criterion of serious threat to life or bodily integrity and a corresponding reaction of fear, terror or helplessness occur, the diagnosis of PTSD should not be made without substantial justification and support from the literature. Otherwise, opposing counsel will, without doubt, question the reliability and credibility of the expert offering the testimony.
In the event of a recognizable traumatic exposure and the presence of psychological symptoms that do not meet the criteria for PTSD, the forensic evaluator should carefully assess whether the individual meets the criteria for other DSM diagnoses. Forensic clinicians should consider whether other mood or anxiety diagnoses are more appropriate (Simon, 2003). These disorders can also be influenced by external events, and many have a higher incidence following a traumatic exposure than does PTSD, and a number of the symptoms of PTSD overlap considerably with the symptoms of such disorders.
Lack of familiarity with DSM diagnostic criteria or excessively flexible and idiosyncratic application of diagnostic criteria or conventions substantially reduces the utility of psychiatric diagnoses. Any assessment of PTSD, even one that concludes in a diagnosis of subthreshold PTSD, must adhere to DSM criteria in order to be credible.