Abstract
Defining the severity of any traumatic experience is of considerable importance both in clinical psychiatry and in the medico-legal setting. While there have been some similarities in the psychiatric approach and the legal approaches to assessing psychological trauma severity, there have also been considerable differences.
Major changes in the DSM definition of psychological trauma (Criterion A of posttraumatic stress disorder [PTSD]), from DSM-III [1] to DSM-IV-TR [2] do not appear to have been based on either empirical data or indeed on common sense; reasons for these substantive changes are unclear. Recent High Court decisions [3] have also changed the legal approach to evaluating psychological trauma in Australia and in contrast to DSM-IV have very much taken a common sense approach; the latter changes not only simplify the legal approach but are flexible and sensible. They are indeed also more consistent with empirical psychiatric findings on the nature of stressors and their relation to psychiatric illness (especially PTSD) than is the case of DSMV-IV Criterion A, a construct that has major problems. The psychiatric and legal approaches to measuring trauma severity are discussed and contrasted.
Methods
A detailed appraisal was made of the recent High Court of Australia decisions [3] in relation to three defining principles or ‘control mechanisms’ in assessing liability for psychological trauma being: (i) ‘sudden shock’; (ii) ‘direct perception’; and (iii) ‘normal fortitude’. These defining criteria were compared with the Criterion A definition of trauma, and both were evaluated in the light of empirical psychiatric evidence pertaining to PTSD.
Results
There have been significant changes in the psychiatric definition of psychological trauma (Criterion A) in the evolution of DSM-III to DSM-IV-TR. Firstly, the range of events or stressors which are eligible has been extended considerably from ‘first-hand’ events (events personally experienced) to also include ‘second-hand’ events. The latter include ‘witnessing or confronting’ events, which happen to others, and to include trauma which is ‘threatened’ to oneself and to others (Criterion A1).
Secondly, there has been a significant conceptual change in definition, in that a traumatic event is no longer defined on the basis of the earlier ‘objective’ or normative standard (DSM-II and III) being a traumatic event which is ‘out of the ordinary’ and would be ‘markedly distressing to almost everyone’, that is the reference point being the average or normal individual. A crucial additional component of the construct now included in DSM-IV (1994) is purely subjective; the subject's own reported response was ‘intense fear, helplessness or horror’ (Criterion A2). The reference point has thus shifted from the average person to the individual in question. These changes are discussed in the light of both empirical psychiatric findings and the recent High Court decisions, which have changed the legal understanding of what is accepted as a ‘traumatic’ stressor.
Extending the range of eligible ‘traumatic’ events (Criterion A1)
The rationale for this has at least some face validity, in that clinicians would agree that people can be traumatized without necessarily being active participants in stressful events (i.e. ‘first hand events’ or being ‘primary victims’). Similarly it is recognized in the life events literature that some substantial second-hand events (witnessing trauma or bad news) may be predictive of subsequent psychiatric morbidity [4].
This approach in DSM-IV seems largely consistent with the High Court's expanded approach [3]. Prior to this judgement it was a requirement that there be a ‘direct perception’ of trauma (i.e. ‘seeing, hearing, touching’) [5], but the judgement in the recent appeal to the High Court sensibly found that adherence to this rule may exclude ‘meritorious claims’. Being a ‘direct participant’ in a traumatic event is thus no longer a requirement; rather, liability for the plaintiff's psychiatric illness (if a ‘secondary’ victim) was dependent on the relationship between the plaintiff (receiving bad news for example) and the primary trauma victim. (The case appealed was on behalf of parents [of a young station worker] both of whom claimed psychiatric injury, on sequentially learning with updated news over a period of time, of the eventual horrific death of their son lost in the outback.) They had no ‘direct perception’ of the events [6]. Equally, the High Court was not prescriptive of the exact nature of the relationship of the primary to secondary victim, inferring obviously that this would be sensibly determined on a case by case basis.
In this regard, both the DSM-IV approach and that of the High Court seem sensible and fair in recognizing that traumatic events come in different forms and that the earlier unduly restrictive definition (‘first hand’ events; ‘direct perception’) was not clinically sound and could be unfair to some meritorious plaintiffs.
Deleting ‘would cause marked distress to almost anyone’ (and replacing it with Criterion A1)
This approach in DSM-IV largely removes the objective or normative standard in judging the severity of a psychological trauma, that is, ‘would be distressing to almost anyone’. The replacement, largely embodied in Criterion A1, is quite problematic. Some elements appear to establish a clinically significant threshold of severity at first sight, for example ‘actual or threatened death or serious injury’. But this can include ‘being confronted with’ (news) or ‘witnessing’ this event occurring ‘to another person’. Thus this could embrace simply hearing of or seeing (e.g. on TV) a tragedy happening to another person. Similarly the trauma of a ‘threat to physical integrity of self or others’ is simply not defined at all. In both these instances, the ‘definition’ of these apparently ‘extreme stressors’ (DSM-IV-TR, p.463) is so great in latitude that both the reliability and more importantly, the construct validity is suspect in these instances. Furthermore the threshold for severity for a traumatic event in these circumstances may be quite low (especially in a medico-legal setting) and this may result in a syndrome with posttraumatic symptoms which are out of proportion to the traumatic event. In these cases the PTSD would be better regarded as an adjustment disorder (albeit with posttrauma symptoms).
This approach is inconsistent with accepted psychiatric research methods in assessing the impact of stressors [4],[7–9] which has good construct and predictive validity, in that stressors judged in this way (i.e. using the average, normal person as the reference point) are reliable, replicable and predict later psychiatric disorders [4]. The High Court has taken a very different stance to that of DSM-IV (Criterion A1) and has reiterated the importance of using the ‘normal fortitude’ rule as a basis for assessing the reasonable ‘foreseeability’ of outcome (i.e. the likely psychiatric impact of a stressful event or trauma), and so to establish legal ‘liability’ for that subsequent psychiatric injury. The basis for establishing legal liability therefore is that first, the trauma should be regarded as likely to produce that type of injury in (normal) people (i.e. it is not farfetched). Second, the respondent, as a ‘reasonable person’, should take action to prevent injury based on that reasonable person's view of both the probability and gravity of injury in a person of normal fortitude [10]. (Both these issues were important in the Tame case in which a teetotal woman driver involved in an MVA, was mistakenly told by a police officer that she was above the 0.05 alcohol limit. This was quickly corrected. Many months later she developed a serious depression and sued the policeman and the Police Department. Her original successful NSW Supreme Court action was overturned by the High Court on both the grounds that such an injury was not foreseeable and that once the mistake was made and corrected, there was no other action a reasonable [policeman] could take to avoid the injury.)
The important issue, namely of ‘vulnerability’ or the eggshell skull (or psyche), is a quite separate issue and is not considered when initially establishing the fact of liability (as the individual's ‘vulnerability’ would not normally be foreseeable). It is however, taken into account later, when assessing the extent of liability, that is, amount of damages payable based on the severity of psychiatric injury sustained [11]. In regard to establishing ‘liability’, the current Criterion A construct, may be very problematic. Since Criterion A1, especially that of ‘threat to physical integrity’ is not defined, and Criterion A2 is obviously subject to distortion by personal vulnerability factors, both are somewhat incompatible with the legal principle of ‘normal fortitude’ which establishes a reference point for judging traumatic events. Criterion A1 will at times need to be regarded very critically by the courts.
The court was also pragmatic and flexible in that ‘foreseeability’ of injury applied, not to having to foresee a specific disorder (e.g. PTSD), but rather the risk of a general class of disorders (i.e. psychiatric disorders) [12]. The High Court furthermore reaffirmed the courts important role in determining foreseeability: the role of the clinical psychiatric expert in judging foreseeability (and normal fortitude) was not considered decisive and would not usurp the court's judgement of the likely ‘foreseeability’ of the traumatic event causing a psychological disorder [12].
The approach of the High Court is not only objective, but is fair and flexible and is indeed more consistent with empirical psychiatric data than is the case with DSM-IV Criterion A.
Inclusion of ‘subjective distress at impact’ (sudden shock) (Criterion A2)
This inclusion of Criterion A2 compounds the above problem (i.e. deletion of the ‘objective’ basis for assessing trauma severity) and increasingly permits trauma to be defined subjectively, in that the person simply reported ‘fear, shock, or horror’ at impact.
Empirical evidence does not support this approach. First, reporting ‘emotional shock’ is unreliable. There is a 75% error rate in the test-retest reporting of emotional shock and the presence of PTSD correlates strongly with this lack of reliability. In addition PTSD symptoms cause an increase in retrospective reports of trauma severity with the passage of time [13]. Second, emotions at impact are a poor predictor of subsequent psychological morbidity. In one review of 34 studies of PTSD ‘shock’ was reported as a predictor of PTSD in only three [14], although this may be an underestimate. Furthermore, if a statistically significant relationship is found it can be clinically insignificant [15]. Similarly, life events research indicates the immediate response to an event is a poor predictor of psychological morbidity [8]. These findings challenge the predictive validity of this element (A2) of the PTSD construct of an ‘extreme traumatic stressor’.
Further, it has also been shown that there is a weak relationship between objective ‘trauma severity’ and the resultant ‘emotional shock’ in normal subjects [15]. The emotional response to stressors however, is strongly associated with personality variables [16], [17] and indeed may be heritable [18].
There are also other problems of bias with ‘sudden emotional shock’, particularly in the medico-legal setting. First, it may appear to falsely validate the severity of the traumatic event; a ‘severe’ emotional response at impact may give false credence to there having been a ‘severe’ trauma. Second, sudden shock may give false credence to subsequent severity of symptoms and suffering; a self-reported severe shock response appears to validate the severity of current symptoms of PTSD. Finally, the ‘sudden shock’ requirement (for PTSD) may unfairly exclude some subjects with significant symptoms of PTSD (Criteria B,C,D, etc.) who, at the time of the trauma did not experience ‘sudden fear, shock or horror’ (Criterion A2); emergency workers for example repeatedly experiencing acute psychological trauma (or those acute experiencing chronic trauma) may be resilient to the acute ‘shock’ response but not to later PTSD symptoms.
Fortunately, the High Court (2002) [3] has dispensed with the ‘sudden shock’ requirement of the earlier (1984) High Court decision [5]. The recent High Court decision (2002) found ‘sudden shock’ would be arbitrary and inconsistent in its application [19], that individuals can sustain psychiatric injury without sudden shock [19] and that liability should hinge on the occurrence of a defined psychiatric disorder and not on some presumed aetiology of that disorder, namely sudden ‘emotional shock’ [20]. This highlights the problem that PTSD is ‘confounded’, embracing both the ‘cause’ and the effect which conflicts with legal principle. The court also noted possible ‘biases’. First, ‘to require sudden shock is to often mandate the contrived search for a particular identifiable triggering event’ (when a chronic or episodic stressor may be present) [21]; and second, the sudden shock requirement may depend on ‘self-serving’ evidence by a plaintiff [21]. There appears considerable logic in the High Court's decision to eliminate the ‘sudden shock’ requirement. The retention of Criterion A2 of DSM-IV in its current subjective form is flawed, inconsistent with empirical evidence, has little predictive validity and may bias court judgement: courts indeed should pay little or no attention to Criterion A2 and should clearly apply the ‘normal fortitude’ principle when assessing severity of any traumatic event, This will also avoid possible biases in clinical appraisal (using Criterion A) which often covertly embrace pre-existing vulnerability, and may distort assessment of relative magnitude of attribution of liability, that is, that due to the specified traumatic event or other aetiological factors, both pre- and posttrauma.
Conclusions
In the psychiatric setting (DSM-IV) and in the High Court [3], there appears one element of consistency in assessing psychological trauma, namely that the ‘eligibility’ of stressful experiences to be possibly considered ‘traumatic’ has been expanded. DSM-IV now includes ‘second-hand’ traumas and the High Court has accepted a similar principle by removing the ‘direct perception’ (‘primary victim’) requirement (‘seeing’, ‘hearing’, ‘touching’). Criterion A1 however, is still not without problems as some components can embrace a wide spectrum of trauma severity and thus, will lack reliability and validity.
In two other crucial respects DSM-IV and Australian law now markedly diverge. First, DSM-IV requires selfreported ‘sudden emotional shock’ (Criterion A2) with all its pitfalls and lack of empirical basis as discussed earlier; the High Court however, has sensibly removed the ‘sudden shock’ requirement. Second, DSM-IV has also largely removed any notion of ‘objectivity’ in defining an extreme traumatic stressor and heavily relies on subjective self-report of emotional impact with all its inherent clinical and methodological limitations, including poor predictive validity.
Thus, many subjects with a diagnosis of PTSD, especially in medico-legal settings, may better fit, conceptually at least, the diagnosis of an adjustment disorder when their severity of symptoms is inconsistent with the severity of the ‘trauma’, at least when judged using the ‘normal fortitude’ approach. (Perhaps DSM-V might include a disorder termed ‘adjustment disorder with posttraumatic symptoms’ to address this problem.) The High Court in contrast, has sensibly retained the ‘normal fortitude’ requirement for judging the notional ‘severity’ of trauma and thus the foreseeability of disorder and ultimately liability for it. The Australian courts therefore not only define psychological trauma in a more ‘sensible’ and objective fashion but do so with a stronger empirical basis than does DSM-IV. It is to be hoped that future court judgements adhere to these ‘normal fortitude’ requirements and are not swayed by expert clinicians valiantly applying DSM-IV definitions of trauma which can overtly or covertly embrace underlying vulnerability and so both distort the establishment of liability and the extent to which it is caused by the nominated ‘traumatic’ event. The simple solution for the courts is to make their ‘diagnosis’ of PTSD on Criteria B–F alone and to separately judge the stressor, using the normal fortitude principle to determine foreseeability and liability.