The European Network for Traumatic Stress
Training & Practice
www.tentsproject.eu
The Prevalence of PTSD
Maja Lis-Turlejska
Learning outcomes (1)
• Describe the concept of prevalence and other
terms used in epidemiological studies: e.g.
incidence rate, and odds ratio (relative risk)
• Describe a change regarding the prevalence of
PTSD studies – from relatively small-scale
studies under clinical conditions to the research
on general population in different countries
Learning outcomes (2)
• Describe the change in prevalence studies
regarding exposure to PTEs and how it is
connected with the Criterion A of PTSD
definition
• Give examples of some often used tools to
measure PTSD and exposure to
potentially traumatic events (PTEs)
Learning outcomes (3)
• Describe the differences between types of
trauma regarding their risk for developing
PTSD
• Describe the prevalence rates of PTSD
(and PTEs) in the studies done recently
in several European countries as well as in
other countries of the world
What is prevalence?
• Prevalence in epidemiological studies of a
disorder means a percentage of a population
that has a disorder at a given time
• In many studies prevalence is discussed in
terms of lifetime prevalence
• Also data are provided on current prevalence of
PTSD in a given time frame, usually one year
Cumulative incidence
• Cumulative incidence („risk”) is the proportion of
people that develop a disorder over time among
only the population at risk for that disorder
• Large cumulative incidence (a large amount of
new disorder occurrence) occurring over a short
period of time has different intervention
implications then if it is observed over a very
long period of time
Risk ratio
• A cumulative incidence ratio („risk ratio” or
„relative risk”) is a relative measure of the
cumulative incidence of disorder in a
group exposed to a certain factor
compared to the cumulative incidence of a
disorder in a group that is unexposed to
that factor
Measuring prevalence of
PTSD and PTEs
• In studies of prevalence measures of
exposure to trauma (potentially traumatic
- event – PTE) and PTSD are used
PTSD measures
• There are two main types of measures
used in PTSD assessment (evaluation):
- Structured Interviews (e.g. CAPS)
- Self-report Questionnaires (e.g. IES)
Measurement of traumatic
event exposure (2)
• DSM-IV introduced two types of changes:
• The range of events considered as
potentially giving rise to PTSD was
broadened, relative to previous definitions
• On the other hand, special significance
was accorded to the individual’s reaction
to the stressor
Measures of exposure to
PTEs
• Data relating to the prevalence of
traumatic events is dependent not only on
the definition of trauma adopted but
equally on the measurement tools being
used
Prevalence studies in
samples of the general population
• In the mid-1990s a significant change took
place regarding epidemiological research
relating to PTSD and – it therefore follows –
exposure to trauma
• This development was from relatively smallscale research under clinical conditions, via
the 1993 research commissioned by the US
Congress into a representative sample of
Vietnam War veterans, culminating in
research on the general population, or on
geographically-based communities
Measurement of traumatic
event exposure
• It is only during the last 20 years that
alongside PTSD-measurement tools there
have appeared scales and questionnaires
designed to measure exposure to various
kinds of traumatic events
• Before - research on PTSD has focused on
those suffering from traumatic experiences
related to participation in combat or war, or in
the wake of other specific types of trauma, such
as natural disasters, rape and criminal assault
Why the studies on
prevalence are important ?
• The work done to establish the PTEs
and PTSD in the general population
permits:
- to estimate the prevalence of exposure
to trauma and of PTSD in the entire
population and its various subgroups
- it also enables the identification of the
types of trauma having the greatest
probability of leading to PTSD
National Comorbidity Survey
(USA)
• Data from research on samples of the
general population, initially undertaken only in
the US; later on began to be carried out in
other Western countries also
• In often cited National Comorbidity Survey
(NCS) (Kessler, et al., 1995) interviews were
administered to a representative national
sample of persons aged 15-54 years
National Comorbidity Survey
(USA)
• Lifetime prevalence of PTSD: 7,8%
• 60.7% of men and 51.2% of women
reported at least one traumatic event
Traumas most commonly
associated with PTSD in NCS
• For men: combat exposure and witnessing
(combat exposure with 6.4% life prevalence
was nominated as most upsetting trauma for
28.8% men with PTSD)
• For women: rape and sexual molestation
(when nominated as most upsetting
probabiblity of PTSD was 45.9% for rape and
26.5% for molestation)
(Kessler, et al., 1995)
NSR-Replication
• Kessler et al. (2005) presented the data from
the replication of NCR conducted between
2001-2003, on the US national sample of
adults, done with the fully structured WHO
Mental Health Survey version of CIDI
• Total PTSD life-time prevalence rate was
6,8 %. Prevalence estimates varied
significantly with age. For PTSD the highest
rate: 9,2% was for a group aged 45-59
Studies on prevalence
of PTSD in Europe
European Study of the Epidemiology of
Mental Disorders (ESEMeD)
- 21,425 adults nationally representative of six
European countries (Belgium, France, Germany,
Italy, the Netherlands and Spain). PTSD lifetime prevalence: Total= 1.9%, (M=0,9%; F= 2.9
%) (Alonso et al., 2004).
- 12 months: Total =1.1% (M=0.5%; 1,7%F
(Darves-Bornoz et. al., 2008)
Prevalence studies in
different European countries
• Study on the lifetime prevalence of PTEs
and PTSD in the Netherlands (de Vries &
Olff, 2009)
- The lifetime prevalence of any potential trauma:
80.7%
- The lifetime prevalence of PTSD: 7.4%
The Zurich Cohort Study
• The weighted lifetime prevalence of PTE
in 1999 was 28%. Of the persons who
reported exposure to PTE (criterion A),
none met all the remaining criteria for
PTSD (Hepp et al., 2006)
PTSD among children and
adolescents
• Studies among children who experienced
specific traumas indicate that children may
have higher prevalence rates of PTSD
then adults in the general population
• US National Survey of Adolescents: sixmonths prevalence: 3.7% for boys and
6.3% for girls (Killpatrick et al., 2003)
Prevalence of PTEs and PTSD
among Danish adolescents
• Ask Elklit (2002) studied prevalence of
traumatic and life events in relation to PTSD in a
Danish national representative sample of 390
eight-grade students aged 13 to 15
• 87% of females and 78% of males were
exposed to at least one event
• Lifetime prevalence of PTSD (according to DSMIII-R) was 9% (5.6% males and 12.3% females)
Study in 4 postconflict
settings
Epidemiological survey conducted among
survivors of war or mass violence (aged >16
years) who were randomly selected from
community populations in Algeria (n=653),
Cambodia (n=610), Ethiopia (n=1200), and
Gaza (n=585).
• The prevalence rate of PTSD was 37.4% in
Algeria, 28.4% in Cambodia, 15.8% in Ethiopia,
and 17.8% in Gaza (de Jong et al., 2001)
Prevalence of PTSD in Eastern
European countries
• There is no data available from the
epidemiological studies done in Eastern
European countries
• Some data however done on non-clinical
samples in Poland and Lithuania show
higher rates of PTSD then in the studies
from Western Europe (Lis-Turlejska, 2005;
Kazlauskas,et. al, 2006)
References
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