Occupational Medicine 2008 58(5):379; doi:10.1093/occmed/kqn062
© The Author 2008. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org
Post-Traumatic Stress Diagnostic Scale (PDS)
Stephen McCarthy
Lansdowne Clinic, Newcastle upon Tyne, UK
E-mail: lansdownepsychol{at}aol.com
 |
A brief history
|
|---|
The Post-traumatic Stress Diagnostic Scale (PDS) was developed
and validated by Edna Foa [
1] to provide a brief but reliable
self-report measure of post-traumatic stress disorder (PTSD)
for use in both clinical and research settings.
|
Description
|
|---|
The scale is intended to screen for the presence of PTSD in
patients who have identified themselves as victims of a traumatic
event or to assess symptom severity and functioning in patients
already identified as suffering from PTSD. The test is self-administered
and can usually be completed within 10–15 min and requires
a reading age of
13 years. The pencil and paper and computerized
scoring versions of the PDS are available from the test distributor
[
2].
Test items mirror DSM IV criteria for PTSD and items are framed in accessible language. Questions relate to the frequency of distressing and intrusive thoughts, post-traumatic avoidance and hyperarousal.
|
Items
|
|---|
The PDS has 49 items. A short checklist identifies potentially
traumatizing events experienced by the respondent. Respondents
then indicate which of these events has troubled them most in
the last month. Respondents then rate their response to this
event at the time of its occurrence to determine whether the
DSM IV stressor criteria are met (Criterion A1 ‘the person
experienced, witnessed or was confronted with an event or events
that involved actual or threatened death or serious injury,
or a threat to the physical integrity of self or others’
and Criterion A2, ‘the person's response involves intense
fear, helplessness, or horror’). Using a four-point scale,
respondents then rate 17 items representing the cardinal symptoms
of PTSD experienced in the past 30 days. Finally, respondents
rate the level of impairment caused by their symptoms across
nine areas of life functioning. A diagnosis of PTSD is made
only when DSM IV criteria A to F are met. The PDS includes a
symptoms severity score which ranges from 0 to 51 and this is
obtained by adding up the individual's responses of selected
items. The cut offs for symptom severity rating are 0 no rating,
1–10 mild, 11–20 moderate, 21–35 moderate
to severe and >36 severe.
|
Validity
|
|---|
The PDS has high face validity because items directly reflect
the experience of PTSD with high internal consistency (coefficient
alpha of 0.92). Test–retest reliability was also highly
satisfactory for a diagnosis of PTSD over a 2- to 3-week period
(kappa = 0.74). Test–retest using symptoms severity scores
yielded a highly significant correlation (0.83). Analysis also
revealed an 82% agreement between diagnosis using the PDS and
the Structured Clinical Interview for DSM [
3].
The PDS does not incorporate any formal scales to detect faking or inconsistent responses. The scale was validated on samples aged 18–65.
|
Key research
|
|---|
The PDS has been used in a wide range of clinical and research
contexts with a high degree of confidence when use of a structured
clinical interview is impractical. PDS has been used in prospective
treatment studies helping establish a role for cognitive behavioural
therapy in those with established PTSD [
4]. Recently, the PDS
has been employed in diagnosing PTSD in the emergency services
[
5].
|
References
|
|---|
- Foa EB. Posttraumatic Stress Diagnostic Scale Manual (1995) National Computer Systems Inc.
- http://www.pearsonassessments.com (3 April 2008, date last accessed).
- Foa EB, Cashman L, Jaycox L, Perry K. The validation of a self-report measure of posttraumatic stress disorder: The Posttraumatic Diagnostic Scale. Psychol Assess (1997) 9:445–451.[CrossRef][Web of Science]
- Duffy M, Gillespie K, Clark DM. Post-traumatic stress disorder in the context of terrorism and other civil conflict in Northern Ireland: randomised controlled trial. Br Med J (2007) 334:1147.[Abstract/Free Full Text]
- Haslam C, Mallon K. A preliminary investigation of post-traumatic stress symptoms among firefighters. Work Stress (2003) 17:277–285.[CrossRef][Web of Science]
CiteULike 
Connotea 
Del.icio.us What's this?
Top
A brief history
Description