Elsevier

Psychiatry Research

Volume 88, Issue 1, 18 October 1999, Pages 63-70
Psychiatry Research

Derivation of the SPAN, a brief diagnostic screening test for post-traumatic stress disorder

https://doi.org/10.1016/S0165-1781(99)00070-0Get rights and content

Abstract

The Davidson Trauma Scale (DTS) is a validated 17-item self-rating scale used in the diagnosis of post-traumatic stress disorder (PTSD), which is sensitive to the effects of treatment. It was felt that a shorter version of the scale might provide a better diagnostic screening tool. Subjects were drawn from a sample of 243 patients obtained from multiple cohorts that included a group of survivors of various forms of trauma, including natural disaster, rape and combat. All subjects had diagnostic assessments for PTSD with a clinical interview and completed the DTS. The data were randomly divided between two subsamples, and frequency and severity scores were calculated for the DTS. A four-item scale, the SPAN (named for its top four items: Startle, Physiological arousal, Anger, and Numbness), was developed. It demonstrated an efficiency of 0.88, sensitivity of 0.84, specificity of 0.91 and positive likelihood ratio of 9.1. In a replication sample, values were slightly lower but still acceptable (efficiency=0.80). A subgroup of PTSD patients received either fluoxetine or placebo in a clinical trial, and a significant SPAN score improvement was observed on fluoxetine. The SPAN, which correlated significantly with the Impact of Events Scale, the Sheehan Disability Scale, and the Structured Interview of PTSD, was found to have a diagnostic accuracy of 88%.

Introduction

Post-traumatic stress disorder (PTSD) is a major mental health issue having a lifetime prevalence in the US of between 8 and 12%. It frequently becomes a chronic problem, and there are substantial rates of psychiatric and medical comorbidity found in association with PTSD (Kessler et al., 1995). Since PTSD was first introduced into the DSM-III (American Psychiatric Association, 1980), the need for accurate diagnosis of PTSD has led to the development of instruments for measuring the disorder.

The structured clinical interview has been regarded as the gold standard of PTSD measurement (Gerardi et al., 1989). These interviews include the Structured Clinical Interview for DSM-III-R (Spitzer et al., 1990), the Structured Interview PTSD measure (SIP) (Davidson et al., 1997a), and the Clinician Administered PTSD Scale (CAPS) (Blake et al., 1995). All have demonstrated good psychometric validity and reliability criteria and have been used extensively in treatment outcome studies.

However, a major drawback of structured clinical interviews is that they are time consuming, and thus, briefer self-rating scales may be viewed as having potential clinical utility. A number of self-rating scales have been developed to assess the symptoms of PTSD while economizing on time. These include the Impact of Events Scale (IES) (Horowitz et al., 1979), the Mississippi Scales for Combat and Non-combat (Keane et al., 1988), the Short Form of the Mississippi Scale (Fontana and Rosenheck, 1994), the Penn Inventory (Hammarberg, 1992), the PTSD Checklist (PCL) (Weathers et al., 1993), the Post-traumatic Stress Diagnostic Scale (PDS) (Foa, 1995), and the Davidson Trauma Scale (DTS) (Davidson et al., 1997b).

Given the abundance of instruments and a rapidly expanding empirical literature, researchers and clinicians can now choose instruments tailored to their particular assessment needs. In addition, they can increase their confidence in assessment decisions by relying on converging information obtained from multiple measures in an assessment battery (Keane et al., 1987). In particular, the use of a structured clinical interview as well as self-rating scales has become widely accepted as a way of obtaining diagnosis and/or assessing severity and clinical significance of symptoms.

The Davidson Trauma Scale (DTS) is a validated 17-item self-rating scale of frequency and severity of each symptom, which is sensitive to the effects of treatment (Davidson et al., 1997b). The DTS reflects the symptoms diagnostic of PTSD as defined in DSM-IV (American Psychiatric Association, 1994). Major strengths of the DTS include its development in a broad population of men and women exposed to different types of trauma, its sensitivity to treatment-induced change across time, and its capability of distinguishing between treatments of differing effectiveness and its ability to predict later treatment response. The full DTS has been shown to distinguish between those with, and those without, a diagnosis of PTSD at a cutoff score of 40, with an efficiency of 0.83.

Since the 17 items of the DTS demonstrate a high level of intercorrelation with one another (Cronbach’s alpha coefficient =0.90), we believed that it might be possible to develop a much shorter version of the scale to serve as a diagnostic screening tool. The newly derived four-item scale (SPAN) forms the subject of this report.

Section snippets

Subjects

Item selection for the SPAN was drawn from a sample of 243 patients obtained from multiple cohorts which comprised both pharmacotherapy trials of lamotrigine (n=14) (Hertzberg et al., unpublished); fluvoxamine (n=12) (Davidson et al., 1998a); nefazodone (n=12) (Davidson et al., 1998b); and fluoxetine vs. placebo (n=55) (Connor et al., 1999); a family study of rape trauma (n=74) (Davidson et al., 1998c); an evaluation of Hurricane Andrew survivors (n=53) (Davidson et al., 1997b); and a group of

Results

A total of 243 patients were included in the analysis. The average age was 37 years (S.D.=11.6). Of the total group, 72% were women, 28% were men, 77.6% were Caucasian and 17.4% were African–American, and 5% were of other ethnic groups. All subjects were evaluated for a diagnosis of PTSD. Of the subjects 118 (48.6%) had a diagnosis of PTSD, while 125 subjects (51.4%) had no diagnosis of PTSD. The demographic data were calculated for both derivation and replication groups as shown in Table 1.

Discussion

We found that a short four-item version of the DTS closely corresponded to the diagnosis of PTSD by structured clinical interview and believe, therefore, that it could be effectively used to screen for the diagnosis. We refer to this scale as the SPAN, a readily usable acronym, which conveys its content in the following way: Startle, Physiological arousal, Anger and Numbness. Based upon SPAN scores, appropriate subjects could then receive a more in depth clinical evaluation. The four-item

Acknowledgements

Thanks are due to Drs Thomas Mellman, Jean Beckham, Michael Hertzberg, and Larry Tupler. This study was supported, in part, by grants from the National Institute of Mental Health (1RO1-MH44740 and RO1-MH47488) to Dr Davidson.

References (31)

  • M.W. Bernadt et al.

    Comparison of questionnaire and laboratory tests in the detection of excessive drinking and alcoholism

    Lancet

    (1982)
  • J.R.T. Davidson et al.

    A family study of chronic post-traumatic stress disorder following rape trauma

    Journal of Psychiatric Research

    (1998)
  • J.P. Allen et al.

    Self-report screening tests for alcohol problems in primary care

    Archives of Internal Medicine

    (1995)
  • American Psychiatric Association, 1980. Diagnostic and Statistical Manual of Mental Disorders. 3rd ed. Washington,...
  • American Psychiatric Association, 1994. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington,...
  • A.T. Beck et al.

    Screening depressed patients in family practice: a rapid technique.

    Postgraduate Medicine

    (1972)
  • A.T. Beck et al.

    An inventory for measuring depression.

    Archives of General Psychiatry

    (1961)
  • D.D. Blake et al.

    The development of a clinician-administered PTSD scale

    Journal of Traumatic Stress

    (1995)
  • K.A. Bradley

    Screening and diagnosis of alcoholism in the primary care setting

    Western Journal of Medicine

    (1992)
  • N Breslau et al.

    Short Screening Scale for DSM-IV Posttraumatic Stress Disorder

    American Journal of Psychiatry

    (1999)
  • B.J. Carroll et al.

    The Carroll Rating Scale for Depression. I. Development reliability and validation

    British Journal of Psychiatry

    (1981)
  • Connor, K.M, Sutherland, S.M., Tupler, L.A., Malik, M.L., Davidson, J.R.T., 1999. Fluoxetine in post-traumatic stress...
  • J.R.T. Davidson et al.

    Structured Interview for PTSD (SIP): psychometric validation for DSM-IV criteria

    Depression and Anxiety

    (1997)
  • J.R.T. Davidson et al.

    Assessment of a new self-rating scale for post-traumatic stress disorder

    Psychological Medicine

    (1997)
  • J.R.T. Davidson et al.

    Fluvoxamine in civilians with posttraumatic stress disorder

    Journal of Clinical Psychopharmacology

    (1998)
  • Cited by (129)

    View all citing articles on Scopus
    View full text