Content uploaded by Catrin Lewis
Author content
All content in this area was uploaded by Catrin Lewis on Oct 29, 2014
Content may be subject to copyright.
Systematic Review of
Psychological First Aid
Jonathan I Bisson
Reader in Psychiatry
Cardiff University
and
Catrin Lewis
PhD Student
Cardiff University
Commissioned by the World Health
Organisation
Systematic Review of Psychological First Aid – 31 July 2009
2
Psychological distress is common following extreme stressors (potentially
traumatic events), often short-lived but problematic in a significant minority.
More marked reactions include the development of psychiatric disorders such
as post-traumatic stress disorder (PTSD), depressive disorders, anxiety
disorders and substance use disorders. Attempts to develop early
interventions that can prevent the development of these disorders have
yielded disappointing results and there remains considerable debate
regarding how best to respond to the psychosocial needs of those affected by
traumatic events.
Systematic reviews have found no convincing evidence for the ability of any
psychosocial intervention directed at everyone involved shortly after a
traumatic event to reduce mental health symptoms
1
. This is true for single
session interventions such as individual psychological debriefing
2
and multiple
session interventions including those based on cognitive behavioural
therapy
3
. Thankfully, there is room to be more optimistic regarding the
efficacy of trauma focused cognitive behavioural therapy when delivered to
individuals who have developed either acute stress disorder or acute post-
traumatic stress disorder
4
. This has led to the recommendation that trauma
focused cognitive behavioural therapy is delivered to individuals who develop
these diagnoses
1
.
Given the evidence available at present, it can be argued that no formal
intervention should be delivered following traumatic events unless individuals
develop a diagnosable condition. The option of doing nothing, however, risks
promoting a sense of lack of social support in those affected which has been
associated with the development of PTSD following traumatic events
5,6
. Many
guidelines caution against doing nothing shortly after traumatic events,
arguing for the delivery of supportive, practical and pragmatic input in a
supportive and empathic manner but avoidance of formal clinical
interventions
1,7,8
. Such approaches do not resemble psychological
treatments, in contrast to most of the early interventions that have been
subjected to randomised controlled trials. They are psychosocial with key
social elements that address people’s basic needs, such as housing, finances
and nutrition.
Such approaches have been advocated as important for many years and the
term Psychological First Aid (PFA) is not a new one
9
. More recently and
driven by the work of the National Centre for Post-Traumatic Stress Disorder
(NC-PTSD) in the United States of America PFA has been developed into a
specific intervention
10
. PFA has become very popular and is increasingly
used and recommended. The cautions against the use of individual
psychological debriefing and the absence of an evidence based early
intervention to recommend
1
have fuelled the popularity of PFA. The term
PFA, however, like other terms such as counselling and debriefing, is often
used as a blanket term to describe a range of different approaches and would
benefit from more formal definition. NC-PTSD define PFA as:
Systematic Review of Psychological First Aid – 31 July 2009
3
‘an evidence informed, modular approach for assisting people in the
immediate aftermath of disaster and terrorism to reduce initial distress and to
foster short and long-term adaptive functioning.’
The NATO guidelines on psychosocial care for people affected by disasters
and major incidents
8
usefully describe PFA as:
“not a single intervention or treatment but an approach that is designed to
respond to people’s psychosocial needs after major incidents or disasters
which comprises of a number of elements”.
The Sphere Handbook describes PFA as:
" basic, non-intrusive pragmatic care with a focus on: listening but not forcing
talk; assessing needs and ensuring that basic needs are met; encouraging but
not forcing company from significant others; and protecting from further harm."
The Inter-Agency Standing Committee (IASC)
11
describe PFA as:
“…..is often mistakenly seen as a clinical or emergency psychiatric
intervention. Rather, it is a description of a humane, supportive response to a
fellow human being who is suffering and who may need support. PFA is very
different from psychological debriefing in that it does not necessarily involve a
discussion of the event that caused the distress.”
The key components of PFA described by NATO, IASC and a joint UK-USA
group of experts
12
are listed alongside each other in Table 1.
Table 1: Components of Psychological First Aid
UK-USA Group
12
NATO
8
IASC
11
Active listening Providing comfort and
consolation
Protecting from
further harm
Reassurance through
normalisation
Protecting people from
further threat and
distress
Providing the
opportunity for
survivors to talk
about the events,
but without
Pressure and
respecting the wish
not to talk
Provision of appropriate and
supportive advice and
information to include self
care and self monitoring
Providing immediate
physical care
Listening patiently
in an accepting
and non-
judgemental
manner
Helping people to identify
problems they cannot handle
Encouraging goal
orientated and
purposeful behaviour
Conveying genuine
compassion
Modelling helpful reactions to
traumatic stress
Helping people to
reunite with loved ones
Identifying basic
practical needs
Systematic Review of Psychological First Aid – 31 July 2009
4
and ensuring that
these are met
Advice and guidance on
maintaining a lifestyle
favourable to mental health
and wellbeing
Enabling voluntary
sharing of experiences
Asking for people’s
concerns and
trying to address
these
Providing information on how
and when to refer themselves
Linking survivors with
sources of support
Discouraging
negative ways of
coping (specifically
through use of
substances
Specific attention to the
needs of children, young
people and other specific
groups
Facilitating a sense of
being in control
Encouraging
participation in
normal daily
routines (if
possible) and use
of positive means
of coping
Helping people understand
the needs and reactions of
others and how they can
support others
Identifying people who
need further help
(triage)
Encouraging, but
not forcing,
company from one
or more family
member or friends
Referral to other more
specialist or supportive
services where indicated
As appropriate,
offering the
possibility to return
for further support
Considering and addressing
ethical matters
As appropriate,
referring to locally
available support
mechanisms or to
trained clinicians
Evaluating risk (including
suicide risk)
PFA continues to be described as an evidence-informed approach but has not
yet been subjected to a formal systematic review of its effectiveness. In order
to address this, the World Health Organisation commissioned us to conduct a
systematic review to determine the current evidence base. As we were not
aware of any randomised controlled trials of PFA we decided to consider any
data containing study regarding its effectiveness. We also conducted a
systematic review of predictors of PTSD and depression to determine if there
were other sources of research that could inform its potential effectiveness.
Systematic Review of Psychological First Aid – 31 July 2009
5
Methods and Results
Systematic review of Psychological First Aid (PFA)
Using the search terms ‘psychological first aid’ and ‘PFA’ the 16 widely used
online bibliographic databases listed in Table 2 were searched.
Table 2: Online bibliographic databases searched
AMED (Allied and Complementary Medicine)
ASSIA (Applied Social Sciences Index and Abstracts)
British Nursing Index and Archive
CINAHL (Cumulative Index to Nursing & Allied Health Literature)
Cochrane Central Register of Controlled Trials (CENTRAL)
Cochrane Database of Systematic Reviews (CDSR)
EMBASE (Excerpta Medica)
HMIC (Health Management Information Consortium)
ISI Science Citation Index
ISI Social Sciences Citation Index
International Bibliography of the Social Sciences (IBSS)
MEDLINE
MEDLINE In-Process & Other Non-Indexed Citations
PILOTS
PsychINFO
Sociological Abstracts
The search yielded 779 citations which were imported into EndNoteX1
reference management software. Removal of duplicates resulted in 516
abstracts for consideration. These were scrutinized one by one to ascertain
potential relevance. 298 were removed on the basis that they did not relate to
PFA or disaster response. This left 218 abstracts for more in depth
consideration. Of these only 74 were directly related to PFA and none
contained any data. These articles provided description, commentary, expert
opinion or discussion of PFA. This search revealed no RCTs, observational or
any other empirical study of PFA.
Systematic review of existing systematic reviews of
protective/risk factors for PTSD
The databases listed in Table 2 were searched using the terms ‘PTSD’, ‘Post
traumatic stress disorder’ and ‘traumatic stress’ combined with the terms
‘predictors’, ‘risk factors’, ‘resilience’ and ‘protective’ limited only to ‘reviews’.
The search revealed 901 citations. Removal of duplicates left 798. Reviewing
the abstracts revealed 70 reviews of the literature related to protective/risk
factors for PTSD. 15 were systematic reviews. The reference sections of
these papers were checked for additional systematic reviews, none were
found. Table 3 summarises the results of the systematic reviews identified.
Systematic Review of Psychological First Aid – 31 July 2009
6
The quality of the reviews included was variable and the reviews of Brewin et
al and Ozer et al remain the most comprehensive ones in the field. Only five
of the reviews included a meta-analysis, two of which only considered peri-
traumatic dissociation. In these five studies, the factors associated with the
presence of PTSD with an effect size over 0.2 were peri-traumatic
dissociation, lack of social support post trauma, trauma severity, life stress
post-trauma, perceived life-threat and peri-traumatic emotional response. In
children the associated factors were pre-trauma psychopathology, threat to
life and pre-trauma parental distress. All effect sizes were weighted average
correlations (Pearson’s r)
Systematic Review of Psychological First Aid – 31 July 2009
7
Table 3: Systematic reviews of risk/ protective factors for PTSD
Author Year
Traumatising
event(s)
Age
Group
Risk / protective
factors examined
Number
of
studies
included
Average effect size (r)/
Conclusion
Breh et al
13
2007
Various
traumas
Adults Peri-traumatic
dissociation
35 Peri-traumatic dissociation = 0.36
Brewin et al
5
2000
Various
traumas
Adults Gender
Age
Socio-economic status
Education
Intelligence
Race
Pre-trauma
psychopathology
Childhood abuse
Prior trauma
Other adverse childhood
Family psychiatric
history
Trauma severity
Lack of social support
Life stress
77 Gender (female) = 0.13
Age (younger) = 0.06
Socio-economic status (lower) = 0.14
Education (lack of) = 0.10
Intelligence (lower) = 0.18
Race (minority status) = 0.05
Pre-trauma psychopathology = 0.11
Childhood abuse = 0.14
Prior trauma = 0.12
Other adverse childhood = 0.19
Family psychiatric history = 0.13
Trauma severity = 0.23
Lack of social support = 0.40
Life stress = 0.32
Bruce
14
2006
Childhood
cancer
survivors and
their parents
All ages Parent sex
Age of child
Socioeconomic status
Time off treatment
Prior stressful life events
24 Parent sex – “mothers of childhood cancer
survivors exhibited higher rates of cancer-
related PTSS than fathers”
Age of child – one study supported
Socioeconomic status – “some findings
Systematic Review of Psychological First Aid – 31 July 2009
8
Family support
Social support
Coping style
support the relationship between lower
socioeconomic status and PTSS, others find
the opposite”
Time off treatment – “the vast majority of
studies of studies reported no correlation
between time off treatment and PTSS”
Prior stressful life events – “both quantity
and quality of prior stressful life events were
shown to be associated with increased rates
of developing cancer related PTSD”
Family support – “greater family support
was associated with fewer PTSS”
Cox et al
15
2008
Accidental
traumatic
injury
Children
and
adolescents
Gender
Age
Pre-trauma
psychopathology
Injury severity
Threat to life
Prior trauma
Involvement of
family/friends in trauma
Pre-trauma parental
distress
14 Gender (female) = 0.18
Age (younger) = -0.04
Pre-trauma psychopathology = 0.22
Injury severity = 0.09
Threat to life = 0.38
Prior trauma = 0.08
Involvement of family/friends in trauma =
0.09
Pre-trauma parental distress = 0.29
Davydow et
al
16
2008
Individuals
admitted to
ICU
All ages Gender (female)
Age (younger)
Agitation in ICU
Physical restraint
Medication
Post ICU memories
15 No meta analysis.
The following predictors were identified:
Gender (female) – significant in 2 of 7
studies
Age (younger) – significant in 4 of 8 studies
Agitation in ICU – significant in 1 of 1 study
Systematic Review of Psychological First Aid – 31 July 2009
9
Anxiety or depression
post ICU
Physical restraint - significant in 1 of 1 study
Anxiety or depression post ICU – significant
in 1 of 2 studies
Various factors to do with medication were
found significant in 1 or more study
Various factors to do with post ICU
memories were found significant in 1 or
more study
Gidron et al
17
2002
Terrorist
attacks
All ages Injury severity
Fear
Feeling treatment was
helpful
Depression
Dissatisfaction with crisis
support
6 No meta analysis
Conclusion:
“the literature is inconsistent concerning the
role of injury severity as a predictor of
PTSD”
Other factors discussed only in relation to
individual studies.
Johnson et
al
18
2008
Civilian
survivors of
war trauma
and torture
Adults Dose
Gender
Age
Refugee variables
Unclear No meta analysis.
Conclusions were as follows:
Dose – “there appears to be consistent
evidence of a dose-effect relationship
between cumulative trauma and the
development and maintenance of PTSD”
Gender – “there is also some evidence that
females are at higher risk than males for
developing PTSD”
Age – “there is also some evidence that
those of older age are more at risk of
developing PTSD”
Systematic Review of Psychological First Aid – 31 July 2009
10
Refugee variables – “although there is a
dearth of studies investigating the impact of
refugee variables on the development of
PTSD it is likely that variables such as
uncertain refugee status and obstacles to
employment and lack of social support
exacerbate symptoms and contribute to
their maintainance”
Lensvelt-
Mulders et al
19
2008
Various
traumas
All ages Peri-traumatic
dissociation
59 Peritraumatic dissociation = 0.401
Olofsson et al
20
2009
RTAs Children
and
adolescents
Perceived threat
Gender (female)
Anxiety and depression
symptoms
Increased parental
vigilance after RTA
(reported by child)
Involvement in car
accidents
Child and parent PTSS
symptoms at 4-6 weeks
12 No meta analysis:
The following were significant risk factors in
multiple studies:
Perceived threat
Gender (female)
Anxiety and depression symptoms
The remainder were predictive in single
studies:
Increased parental vigilance after RTA
(reported by child)
Involvement in car accidents
Child and parent PTSS symptoms at 4-6
weeks
Ozer et al
6
2003
Various
traumas
Adults Prior trauma
Prior psychological
adjustment
Family history of
psychopathology
68 Prior trauma – 0.17
Prior psychological adjustment – 0.17
Family history of psychopathology – 0.17
Perceived threat to life – 0.26
Social support post-trauma - -0.28
Systematic Review of Psychological First Aid – 31 July 2009
11
Perceived threat to life
Social support post-
trauma
Peri-traumatic emotional
response
Peri-traumatic
dissociation
Peri-traumatic emotional response – 0.26
Peri-traumatic dissociation – 0.35
Tedstone et
al
21
2003
Medical
illness and
treatment
Adults Existing characteristics
(e.g. personality,
previous life adversity,
previous mental health
difficulties)
Age
Aspects of trauma itself
Medication
14 No meta analysis.
The following conclusions were drawn:
Existing characteristics (e.g. personality,
previous life adversity, previous mental
health difficulties) – “may dispose
individuals to the development of PTSD”
Age – “there is mixed evidence concerning
the impact of age on the development of
PTSD in the physical health literature”
Aspects of trauma itself – “may also
predispose individuals to the development
of PTSD”
Medication – “little is known about how
these drugs may impede or enhance trauma
processing”
Tolin et al
22
2006
Various
traumas
All ages Gender 290 “Meta analyses of studies yielding sex-
specific risk of potentially traumatic events
and PTSD indicated that female participants
indicated that female participants were more
likely than male participants to meet criteria
for PTSD(I couldn’t see an effect size)
Van der Hart 2008
Various All ages Peri-traumatic 53 No meta analysis
Systematic Review of Psychological First Aid – 31 July 2009
12
et al
23
traumas (only one
study
pertained to
children)
dissociation Conclusion:
“the majority of the empirical studies
reviewed supported the notion that the
experience of dissociative symptoms during
a potentially traumatising event increases
the risk of developing PTS”
Van der
Velden
24
2008
Various
traumas
All ages Peri-traumatic
dissociation (PD)
17 No meta analysis.
Conclusion:
“this systematic review demonstrates that
the majority of prospective studies found no
indications that PD is an independent
predictor for PTSD symptomatology 3
months or later after type I traumatic events,
although several studies reported a
significant cross-sectional or bivariate
association between PD and PTSD
symptomatology”
Systematic Review of Psychological First Aid – 31 July 2009
13
Systematic review of existing systematic reviews of
protective/risk factors for depression after disaster/ traumatic
events
Using the search terms ‘depression’ combined with the terms ‘predictors’, ‘risk
factors’, ‘resilience’ and ‘protective’ together with ‘trauma’, ‘traumatic’,
‘disaster’ limited only to ‘reviews’ the online databases shown in Table 1 were
searched. The search yielded 3473 citations which were imported into
EndNoteX1 reference management software. Removal of duplicates resulted
in 2598 for consideration. These were scrutinized one by one to ascertain
potential relevance. This search however revealed no systematic reviews of
risk factors for depression after traumatic events.
Discussion
The absence of quantitative data containing evidence to support PFA makes it
impossible to determine whether it is effective or not following traumatic
events. It is apparent, however, that certain factors, in particular peri-
traumatic dissociation and perceived poor social support, are associated with
raised rates of PTSD. This provides support for the argument that effective
interventions should address these two factors. A recent Delphi study of over
100 experts, performed to develop the European Network for Traumatic
Stress’s (TENTS) Guidelines on psychosocial care following disasters
7
, found
strong consensus that, despite the absence of direct evidence, social care
should be provided for those involved in disasters
25
. There was also strong
consensus that responses should promote a sense of safety, self and
community efficacy/empowerment, connectedness, calm and hope. This is in
keeping with and informed by the work of Hobfoll and colleagues who argued
that indirect evidence pointed to these factors as being guiding principles for
early to mid-level intervention following disaster and mass violence
26
. The
TENTS Delphi study also found strong consensus for the provision of general
support, access to social support, physical support and psychological support.
The TENTS guidelines - like the IASC Guidelines - recommend that the
interventions provided to individuals should only be done with full
consideration of individuals’ wider social environment, especially their families
and communities
7
. They advocate the provision of practical help and
pragmatic support in an empathic manner. These recommendations are
consistent with the principles of PFA and are supported by the findings of our
systematic review of systematic reviews of predictors. They are also
consistent with considerable anecdotal evidence that individuals fare badly if
they feel they are not supported, particularly by those they feel should be
supporting them, for example employers or people in positions of authority.
It is clear that the principles of PFA have much in common with the
approaches recommended in guidelines for psychosocial responses following
major traumatic events and are supported by evidence that lack of social
support is associated with poorer outcome. It therefore seems reasonable to
Systematic Review of Psychological First Aid – 31 July 2009
14
advocate the use of interventions based on the principles of PFA, as several
guidelines do
8,11,12,27
although most fall short of recommending PFA as a
manualised step-by-step intervention. We would also caution against this
given the absence of direct evidence for PFA or any other formal intervention
for everyone involved in a traumatic event. Hobfoll et al
26
argue that there
are many ways to operationalise the five principles they identified and the
need for careful design of interventions that are tested in pilot programs,
refined, retested, and further evaluated before being implemented. They also
caution against hopes that such interventions will be an ultimate panacea that
prevent long-term difficulties and emphasise the need to consider cultural
factors, a point that led the NC-PTSD to note a potential limitation of its PFA
guide as its specific development for use in Western settings.
IASC’s guidance recommends the provision of PFA by “a variety of
community workers” for people in “acute trauma-induced distress”
11
. This is
consistent with Sphere’s recommendation that PFA is available to acutely
distressed individuals after traumatic events. IASC argue that some forms of
psychological support (“very basic psychological first aid”) for people in acute
psychological distress do not require advanced knowledge and can easily be
taught to workers who have no previous training in mental health. It seems
important that the principles of PFA can be taught quickly to both volunteers
and professionals
27
and that PFA is not seen as, and does not become, a
formal clinical intervention.
The NATO Guidelines favour the principles of PFA as an appropriate basis for
psychosocial plans because:
“the abilities of people to accept and use social support and the availability of
it are two of the key features of resilience.”
In common with others,
1,28
the NATO guidelines advocate a stepped model of
care, in which the needs of people determine the level of support they receive.
PFA is a key component in this model as shown in Table 4.
Table 4: NATO Stepped Care Model - the six main components
Strategic planning - multi-agency to include preparation, training and
rehearsal
Prevention services - planned and delivered in advance to develop
communities’ psychosocial resilience
Basic humanitarian and welfare services available to everyone
Psychological first aid delivered by trained and supervised lay persons
Screening, assessment and intervention services for people with ongoing
distress
Access to primary and secondary mental healthcare services for people who
are assessed as requiring them.
In summary, there is an absence of direct evidence for the effectiveness of
PFA but indirect evidence supports the delivery of services based on the
principles of PFA in the first few weeks after a traumatic event. We agree that
when delivered PFA should be consistent with research evidence on risk and
Systematic Review of Psychological First Aid – 31 July 2009
15
resilience following trauma; applicable and practical in field settings;
appropriate for developmental levels across the lifespan; and culturally
informed and delivered in a flexible manner
8
.
References
1. [NCCMH] National Collaborating Centre for Mental Health. Post-traumatic
stress disorder: The management of PTSD in adults and children in primary
and secondary care. London and Leicester: Gaskell and BPS (2005).
2. Rose S, Bisson J, Churchill R et al. Psychological debriefing for preventing
post traumatic stress disorder (PTSD). The Cochrane Database of Systematic
Reviews, Issue 3 (2005).
3. Roberts, N., Kitchiner, N., Kenardy, J., Bisson, J.I. Multiple session early
psychological interventions for the prevention of post-traumatic stress
disorder. Cochrane Database Systematic Review, 3, CD506869 (2009).
4. Roberts, N., Kitchiner, N., Kenardy, J., Bisson, J.I. Systematic review and
meta-analysis of multiple session early interventions for traumatic events.
American Journal of Psychiatry, 166, 293-301 (2009).
5. Brewin, C. R., Andrews, B. & Valentine, J. D. Meta-analysis of risk factors
for posttraumatic stress disorder in trauma-exposed adults. Journal of
Consulting and Clinical Psychology 68, 748-766 (2000).
6. Ozer, E. J., Best, S. R., Lipsey, T. L. & Weiss, D. S. Predictors of
posttraumatic stress disorder and symptoms in adults: A meta-analysis.
Psychological Bulletin 129, 52-73 (2003).
7. TENTS Project Partners. The TENTS guidelines for psychosocial care
following disasters and major incidents. Downloadable from
http://www.tentsproject.eu (2009).
8. North Atlantic Treaty Organisation (NATO). Annex 1 to
EAPC(JMC)N(2008)0038 Psychosocial care for people affected by disasters
and major incidents: a model for designing, delivering and managing
psychosocial services for people involved in major incidents, conflict,
disasters and terrorism. Brussels: NATO (2009).
9. Tyhurst, J. S. Individual reactions to community disaster: the natural history
of psychiatric phenomena. American Journal of Psychiatry, 107, 764–769
(1951).
10. National Child Traumatic Stress Network and National Center for PTSD.
Psychological First Aid: Field operations guide. 2
nd
Edition, (2006).
Systematic Review of Psychological First Aid – 31 July 2009
16
11. Inter-agency standing committee (IASC). IASC guidelines on mental health
and psychosocial input support in emergency situations. Geneva: IASC, (2007).
12. Joint UK – USA Workshop. Catastrophe Mental Health Emergency
Planning, Mental Health & Catastrophic Events; Policy & Practice
Implications. Omagh: NICTT (2008).
13. Breh, D. C. & Seidler, G. n. H. Is peritraumatic dissociation a risk factor for
PTSD? Journal of Trauma and Dissociation 8, 53-69 (2007).
14. Bruce, M. A systematic and conceptual review of posttraumatic stress in
childhood cancer survivors and their parents. Clinical Psychology Review 26,
233-256 (2006).
15. Cox, C. M., Kenardy, J. A. & Hendrikz, J. K. A meta-analysis of risk factors
that predict psychopathology following accidental trauma. Journal of
Specialists in Pediatric Nursing 13, 98-110 (2008).
16. Davydow, D. S., Gifford, J. M., Desai, S. V., Needham, D. M. & Bienvenu,
O. J. Posttraumatic stress disorder in general intensive care unit survivors: a
systematic review. General Hospital Psychiatry 30, 421-434 (2008).
17. Gidron, Y. & Gidron, Y. Posttraumatic stress disorder after terrorist
attacks: a review. Journal of Nervous & Mental Disease 190, 118-21 (2002).
18. Johnson, H., Thompson, A., Johnson, H. & Thompson, A. The
development and maintenance of post-traumatic stress disorder (PTSD) in
civilian adult survivors of war trauma and torture: a review. Clinical
Psychology Review 28, 36-47 (2008).
19. Lensvelt-Mulders, G. et al. Relations among peritraumatic dissociation
and posttraumatic stress: A meta-analysis. Clinical Psychology Review 28,
1138-1150 (2008).
20. Olofsson, E., Bunketorp, O. & Andersson, A. L. Children and adolescents
injured in traffic - associated psychological consequences: a literature review.
Acta Paediatrica 98, 17-22 (2009).
21. Tedstone, J. E., Tarrier, N., Tedstone, J. E. & Tarrier, N. Posttraumatic
stress disorder following medical illness and treatment. Clinical Psychology
Review 23, 409-48 (2003).
22. Tolin, D. F., Foa, E. B., Tolin, D. F. & Foa, E. B. Sex differences in trauma
and posttraumatic stress disorder: a quantitative review of 25 years of
research. Psychological Bulletin 132, 959-92 (2006).
23. Van der Hart, O., Van Ochten, J. M., Van Son, M. J. M., Steele, K. &
Lensvelt-Mulders, G. Relations among peritraumatic dissociation and
posttraumatic stress: a critical review. Journal of Trauma and Dissociation 9,
481-505 (2008).
Systematic Review of Psychological First Aid – 31 July 2009
17
24. van der Velden, P. G., Wittmann, L., van der Velden, P. G. & Wittmann, L.
The independent predictive value of peritraumatic dissociation for PTSD
symptomatology after type I trauma: a systematic review of prospective
studies. Clinical Psychology Review 28, 1009-20 (2008).
25. Bisson JI, Tavakoly B, Witteveen A, et al. TENTS Guidelines:
development of post-disaster psychosocial care guidelines through a Delphi
process (Under Review).
26. Hobfoll SE, Watson P, Bell CC et al Five Essential Elements of Immediate
and Mid–Term Mass Trauma Intervention: Empirical Evidence. Psychiatry, 70,
283-315 (2007).
27. The Sphere Project. Humanitarian Cahrter and Minimum Standards in
Disaster Response. Oxford: Oxfam Publishing (2004).
28. Bisson, J.I., Roberts, N. & Macho, G. The Cardiff traumatic stress
initiative: an evidence-based approach to early psychological intervention
following traumatic events. Psychiatric Bulletin, 27, 145-147 (2003).