Expert Witness Journal Issue 67 June/July 2026 - Flipbook - Page 23
Post-Traumatic Stress Disorder (PTSD) is perhaps
the condition which clinicians will 昀椀rst think of
as a psychiatric complication of physical trauma.
Possibly it is unique among psychiatric disorders
due to a speci昀椀ed requirement for a distressing
event in order for the diagnosis to be made. The
threshold is set fairly high, and a minor trip injury
or low impact RTA would not be expected to lead
to PTSD. ICD-11 requires “event(s) of an extremely
threatening or horri昀椀c nature” eg natural or humanmade disasters, serious accidents, torture, sexual
violence, terrorism, assault or acute life-threatening
illness, witnessing the threatened or actual injury
or death of others in a sudden, unexpected, or
violent manner; and learning about the sudden,
unexpected or violent death of a loved one. Among
the requirements in DSM5 is “Exposure to actual or
threatened death, serious injury”. What is “serious”
in terms of injury or accident is not de昀椀ned. Clearly,
how threatening a particular injury is to a person
will depend on its context and their psychiatric
vulnerability or robustness. But only a minority
of people experiencing an incident meeting the
required threshold will go on to develop PTSD. A
further requirement is that Psychological symptoms
have a signi昀椀cant impact in terms of distress or
altered activities. Of the two classi昀椀cations of
PTSD, ICD-11 is probably the more straightforward
in terms of symptom pro昀椀le. It requires all three of
the following:
1.
Re-experiencing. This could be in the form
of frequent distressing dreams, intrusive
distressing thoughts, or 昀氀ashbacks.
In
psychiatric jargon, the term 昀氀ashbacks has a
speci昀椀c meaning, denoting that the traumatic
event is being experienced again, in the here
and now. It entails a dissociative element and
is di昀昀erent in that sense to a memory. In this
context, a “昀氀ashback”is di昀昀erent to the way the
term is used about a 昀椀lm or movie, denoting
simply an insertion of past events into the
narrative, and it is worth obtaining a description
of what a claimant experiences if this term is
used.
2.
Hypervigilance/hyperarousal. Hypervigilance
is not simply being careful. Anyone who has
had a signi昀椀cant injury will be more careful
next time, and all drivers are expected to
remain vigilant. ICD-11 says that people who
are hypervigilant “constantly guard themselves
against danger and feel themselves or others
close to them to be under immediate threat
either in speci昀椀c situations or more generally.
They may adopt new behaviours designed to
ensure safety (e.g., not sitting with ones’ back
to the door, repeated checking in vehicles’ rearview mirrors)”.
3.
Avoidance. In DSM-5, for PTSD, avoidance
has to be persistent. It can be avoidance of
internal reminders (thoughts, memories,
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feelings) or external reminders (people, places,
activities, discussion). However, in ICD-11, the
requirement is for avoidance not merely of
reminders, but of situations or activity likely to
lead to re-experiencing (eg 昀氀ashbacks).
To screen for PTSD, a rating scale such as the PCL5 (based on the DSM-5 criteria) could be used.
Alternatively, consider a few questions about key
symptoms such as: Do you get dreams or nightmares
about the incident? Is there anything that you will
not do because it reminds you of the incident in a
way that is too upsetting? In what ways are you more
on your guard than before the incident? Was there a
time where you would not go to the place where the
incident happened or do what you were doing at the
time, e.g. driving, sport?
Depression
Depression is used as an everyday synonym for feeling
sad, miserable or fed up. For example, “This weather
makes me feel so depressed”. It is worth reminding
ourselves that the de昀椀nition of clinical depression
is di昀昀erent. Symptoms are more persistent and are
present for most or all of the time over at least two
weeks (usually longer). ICD-11 requires that during
this period, depressed mood or diminished interest
must be present most of the day, nearly every day,
accompanied by other symptoms, such as di昀케culty
concentrating, feelings of worthlessness or excessive
or inappropriate guilt, hopelessness, recurrent
thoughts of death or suicide, changes in appetite
or sleep, psychomotor agitation or retardation, and
reduced energy or fatigue. Importantly therefore,
an episode consisting of low mood that has been
present less than most of the time, with maintained
interest in activities rules out a depressive episode.
Likewise, DSM 5 speci昀椀es similar core symptoms
(with the addition of loss of capacity for enjoyment)
and the additional and core symptoms must make
up a minimum of 5. There is also a requirement
that symptoms are not better explained by another
physiological process or substance.
Various rating or screening scales are sometimes
used. The Beck Depression Inventory and Hospital
Anxiety and Depression Rating Scale (HADS)
have their merits but do not correspond well to
the de昀椀nition of Depression given above. NHS
Psychological Services which operates in England
has adopted the PHQ-9 which is also commonly used
in primary care. The PHQ9 corresponds well to
the DSM5 criteria for Major Depression and unlike
HADS, is copywright free. If the medicolegal expert
is going to use one of these scales, they might choose
the PHQ9 in order that scores may be directly
compared with those used by others. However, as
with all such scales, they should not be regarded by
the Courts as substitutes for a clinical assessment
and nor should scores be interpreted very literally
like blood test results or thermometer readings.
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JUNE 2026
