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Neurolaw Letter, 3: 1992. 19. SBORDONE, R. J. and LITER, J. C.: Mild traumatic brain injury does not produce post-traumatic stress disorder. Brain Injury, 9: ...

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Post-traumatic stress disorder following minor and severe closed head injury: 10 single cases T. M. McMILLAN St George’s Healthcare, Copse Hill, London, UK

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Received 6 November 1995; revised 26 January 1996; accepted 1 February 1996) Post-traumatic stress disorder (PTSD) was found to occur after minor or severe closed head injury in 10 single cases which are reported in detail. They were drawn from 312 cases of closed head injury who were referred for neuropsychological assessment or neurorehabilitation. All cases which had been given both diagnoses are presented. Information was collected retrospectively from case notes and reports. It is argued that a continuum of experience, which represents the entirety of an event, is not necessary for PTSD to occur, but that a `window’ of real or imagined experience which results from loss of consciousness and post-traumatic amnesia after closed head injury need not prevent the symptoms of PTSD from arising, although they may make them less likely and the phenomenon of the dual diagnoses relatively rare. The issue of whether PTSD found following closed head injury is a subclassification of PTSD is raised.

Introduction Post-traumatic stress disorder (PTSD) is an anxiety state which can result from an extreme traumatic experience that involves threatened death or serious injury or other threat to physical integrity. The Diagnostic and Statistical Manual IV [1] sets out six sets of criteria which have to be fulfilled to warrant a diagnosis of PTSD. Although the event iself is characteristically experienced, the victim may later have amnesic gaps for parts of it, and this amnesia is considered to be a stress-related response to the emotional trauma. As a result of severe closed head injury the traumatic event is never recalled, and as a result of less severe head injury the impact/concussive blow is never recalled; this is widely thought to be an organic consequence of the concussional injury. Depending on the nature of the brain injury, retrograde amnesia (RA) may last from virtually nothing or a few seconds to months or even years; RA can be of long duration, and remain so or `shrink’ during recovery [2]. The individual will be unconscious for a period ranging from seconds to months, and then follows a period of confusion and disorientation during which new information is not reliably recalled (i.e. post-traumatic amnesia) [3]. A number of papers have hypothesized neurological mechanisms which might cause PTSD. These have been described as neuroendocrine [4], neuropsychological [5,6] and neuropsychiatric [7]. Most have specifically hypothesized mechanisms linking closed head injury and PTSD without actually providing clear evidence [8± 11]. Correspondence to: T. M. McMillan, M. App. Sci. PhD, FBPsS, Head of Clinical Psychology, Wolfson Medical Rehabilitation Centre and Atkinson Morley’s Hospital, St George’s Healthcare, Copse Hill, London SW20 0NE, UK. 0269± 9052/96 $12 00

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T. M. McMillan

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A few studies have reported single cases of PTSD following mild [12,13] or severe [14] closed head injury. There have also been very few group-based studies on this issue, and those that exist tend to report on PTSD after head injury briefly, as a minor topic in papers largely concerned with other matters [15,16]. For example, Grigsby and Kaye [15] studied the incidence of depersonalization and derealization in 70 whiplash or concussive head injury cases, and found that PTSD had developed in some as a result of the accident. It is likely that all of their patients had not sustained a significant brain injury. Forty-eight reported loss of consciousness (LOC) of 30 minutes or more, and 18 LOC of less than 30 minutes. Few details are given about the 23 cases who had PTSD according to the DSM III-R criteria. Mayou et al. [16] studied psychiatric consequences of road traffic accidents in 188 consecutive cases admitted to accident and emergency departments. As cases with LOC for more than 15 minutes were excluded, any head injuries in the study would be likely to be minor. Details of how severity of brain injury was assessed, or numbers of headinjured cases included, are not specified exactly. PTSD was diagnosed in 11% of the overall sample in the year after the accident, and none of these had brief LOC. The authors concluded that the risk of PTSD developing was relatively low in cases with brief LOC. Acute distress, including descriptions of the accident as `horrifying’, was found to be a risk factor associated with the development of psychological disorders, including travel phobia and PTSD, and was not associated with LOC. Bryant and Harvey [17] investigated acute stress response in patients who had been in road traffic accidents, of which 38 were `mildly’ head-injured and 38 were not headinjured. The head-injured patients were selected on the basis of having PTA of less than 24 hours (hence some may have sustained a moderate head injury), having no recall of events immediately preceding the accident and having no memory for the impact of the accident. They reported that 27% of head-injured, and 42% of nonhead-injured, patients satisfied most diagnostic criteria for PTSD. The exception was the criterion of symptom duration, which could not be reported because of the absence of follow-up. State anxiety was significantly correlated with the intrusion score on the Impact of Events Scale in the non-head-injured group only. Sbordone [18] however, has argued that PTSD and closed head injury are mutually incompatible conditions. The basis of this argument is that, following a neurological amnesia, events cannot be recalled because the head injury victim has no conscious or subconscious recall of the experience. As memories are not emotionally suppressed, it is argued that an anxiety state which is based on re-experience of the traumatic event simply cannot develop. Recently Sbordone and Liter [19] reported comparisons between symptoms reporting in 42 cases of PTSD with no loss of consciousness (LOC) and 28 cases with post-concussional syndrome (PCS), 24 of which were certain that they had lost consciousness (mean LOC 6 2 minutes, SD 12 7 ). Cases previously diagnosed with PCS and PTSD were interviewed to consider whether any could be given both diagnoses. The study was not blind. The authors reported that any recollections of the accident lacked detail in the PCS group when compared to the PTSD group, and no PCS case had PTSD also. They interpreted these data as supporting their argument that PTSD and PCS or minor head injury are mutually incompatible disorders. A difficulty with this position is that it does not explain findings from single cases. For example, McMillan [14] made clear how a case of severe head injury which had a post-traumatic amnesia of 6 weeks qualified for diagnosis of PTSD using the then current DSM III-R classification [20]. This present paper describes a

PTSD after closed head injury

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further 10 cases, who suffered a definite closed head injury which ranged from moderate to extremely severe, and who also complained of symptoms which were consistent with a diagnosis of PTSD.

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Method Information from case notes was collated in 10 patients who had been diagnosed with PTSD which resulted from definite closed head injury. The DSM III± R criteria were used for diagnosis. They were drawn from a series of 312 closed head injury cases seen by the author between January 1989 and October 1995. They are not likely to be representative of the head-injured population as a whole, as they had either been admitted to the Wolfson Rehabilitation Centre for specialist neurorehabilitation or had been referred to the author for an assessment including legal purposes. All cases found with this combination of diagnoses are presented. Loss of consciousness together with evidence of post-traumatic amnesia of 1 hour or more was required for inclusion. If PTA is shorter than this, it is difficult to be certain retrospectively whether or not a concussive injury has been sustained. This restrictive criterion was used simply to ensure that all cases had definitely sustained a brain injury. Information on PTA had originally been obtained from retrospective interview with patient and relative, and wherever possible from scrutiny of accident and emergency/hospital handwritten notes and contemporaneous medical reports. Premorbid IQ had been assessed using the National Adult Reading Test [21] in six cases and using the Spot the Word Test [22] in case 10. Error scores were converted to IQs using the revised NART in every case. Verbal learning was assessed using an auditory verbal learning test which has UK norms [23]. Results In the population of 312 cases the duration of PTA was 1± 24 hours in 17 (5%), was 1± 7 days in 25 (8%), as 1± 4 weeks in 146 (47%) and was over 4 weeks in 124 (40%). The preponderance of very/extremely severe head injuries in this population will simply reflect the reason for referral. Age mean (32 3, SD 12 3, range 15± 69) and sex (75% male) were reasonably representative of serious head injury [24]. Cases with head injury and PTSD (see Table 1) Of the 10 cases with PTSD, head injury resulted from a road traffic accident in eight cases, from an aeroplane crash in one and from an industrial accident in one. Age ranged between 19 and 53 years (mean 33 9, SD 12 3, n = 10). None had any prior history of neurological of psychiatric disorder. Sixty per cent of these cases were female, and this is more than would be expected if considering the epidemiology of head injury (27%) found in a study of consecutively admitted closed head injury cases in north London [24] or the proportion of females found in the population from which this subgroup was drawn (25%). Premorbid verbal IQ ranged from 77 to 122 (mean 100, SD 15, n = 7). Time between injury and assessment varied between 9 and 50 months (mean 30, SD 12, n = 10). In Tables 1± 4 cases are numbered in order of severity of closed head injury, case 1 being the least severe and case 10 the most severe in terms of the duration of post-traumatic amnesia.

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T. M. McMillan Table 1.

Background details and injury characteristics Patient no.

1

2

3

4

5

6

7

8

9

10

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Age at injury 31 47 52 30 29 19 21 53 31 26 (years) Sex F F F F M M M F M F Premorbid VIQ ± 109 122 ± 95 102 107 87 ± 77 Time since 32 50 30 32 09 43 21 22 22 35 injury (months) LOC 5 min

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