A multidimensional spectrum approach to post-traumatic stress disorder: comparison between the Structured Clinical Interview for Trauma and Loss Spectrum (SCI-TALS) and the Self-Report instrument (TALS-SR)
Introduction
Since its first introduction in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition[1], post-traumatic stress disorder (PTSD) has raised increasing interest in clinicians and students of psychiatry and has been progressively investigated in general population samples. Current diagnostic criteria [2] stipulate exposure to an event that threatens serious physical injury of self or others, or that has implicated someone's death, and that is accompanied by feelings of intense fear, helplessness, or horror. Patients can also have confronted these same events by becoming aware of them, not only through direct exposure. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) diagnosis requires development of symptoms in 3 domains that persist for at least a month: re-experiencing (criterion B), avoidance (criterion C), and increased arousal (criterion D) [2]. Criterion level symptoms needed to establish the diagnosis require a threshold level of exposure, a defined immediate response, and a set of persistent symptoms.
Recently, investigators have emphasized the importance of determining whether the event is shocking to the individual or not, regardless of its form in order to define an event as traumatic, that is, able to produce symptoms of traumatic stress (intrusion, numbing, and arousal) [3]. Increasing evidence has documented the role of so-called low-magnitude events (eg, divorce, serious illness, and financial reverses) in determining post-traumatic stress reactions [4], [5], [6]. Conversely, several studies reported significant functional impairment and treatment seeking in a large number of victims who, although exposed to a DSM-IV-TR–qualified trauma, did not fulfill the symptom criteria (B, C, and/or D) [7], [8], [9]. Thus, authors [7], [8], [10], [11], [12] introduced the concepts of partial, subthreshold, or subsyndromal PTSD to better investigate the clinical relevance of these forms. Breslau et al [13], in a latent class analysis of 2 large epidemiologic samples, suggested the existence of a 3-class structure that separates trauma-exposed persons with pervasive disturbance from those with intermediate or no disturbance.
In line with these studies, and in accordance with Moreau and Zisook [6], who conceptualized PTSD as consisting of 3 main dimensions, the nature of the stressor, the possible responses to trauma, and the symptom severity, we have developed a Structured Clinical Interview for Trauma and Loss Spectrum (SCI-TALS) [14]. Considering the requirements stated by the DSM-IV-TR for PTSD, when developing a spectrum assessment of this condition, we considered potentially triggering events, peritraumatic, and persistent symptoms. The SCI-TALS explores stress response syndromes across 3 different dimensions: (1) the dimension of potentially traumatic events, that includes not only the traumatic events considered by the DSM-IV-TR criterion A but also low-magnitude or mild events (eg, failure at school or at work, sexual harassment, abortion), besides a wide continuum of loss events; (2) the dimension of the peritraumatic and acute reactions; (3) the dimension of the post-traumatic spectrum symptoms, including criterion and noncriterion symptoms associated with the DSM-IV-TR diagnosis of PTSD.
The Trauma and Loss Spectrum was developed in the framework of the Spectrum Project and is based on a dimensional approach to psychopathology that considers as clinically relevant not only threshold-level manifestations of PTSD but also atypical symptoms, behavioral traits, and temperamental features associated with established diagnostic constructs. In addition to the instrument described in the present study, the Spectrum Project has developed and validated other psychometrically sound instruments [15], [16], [17], [18], [19], [20] for the assessment of mood, panic-agoraphobic, obsessive-compulsive, social phobic, eating, substance use, and psychotic spectra. All instruments can be downloaded at www.spectrum-project.net. A novel aspect of the “spectrum model” is that the symptoms and traits included in the assessment may occur in isolation rather than as part of a temporally circumscribed clinical syndrome. Research has indicated that spectrum features are associated with considerable suffering and disability and delayed response to treatments, even in the absence of threshold-level psychiatric disorders [21] and that subthreshold symptoms may predict the onset of full blown disorders in non psychiatric patients[22]. Thus, the Trauma and Loss Spectrum assessment instruments differ from current gold standard measures of PTSD, such as the Clinician Administered PTSD Scale (CAPS) [23]. The CAPS, in fact, is a structured clinical interview investigating the DSM-IV criteria for PTSD. Besides assessing the 17 PTSD symptoms, questions target the impact of symptoms on social and occupational functioning, improvement in symptoms since a previous CAPS administration, overall response validity, overall PTSD severity, and frequency and intensity of 5 associated symptoms (guilt for acts committed, survivor guilt, gaps in awareness, depersonalization, and derealization). Low-grade events or subthreshold or atypical posttraumatic reactions, other than the 5 associated symptoms, are not targeted.
Both the interview (SCI-TALS) and the self-report (TALS-SR) instruments consist of 116 items grouped into 9 domains including: loss events (I); grief reactions (II); potentially traumatic events (III); reactions to losses or upsetting events (IV); re-experiencing (V); avoidance and numbing (VI); maladaptive coping (VII); arousal (VIII); and personal characteristics/risk factors (IX).
Recent work has identified a syndrome of complicated grief (CG) as a form of stress response [24], [25], [26], [27], [28], [29]. Studies have increasingly defined the key features of this new psychopathologic entity to include emotional reactions to the death such as disbelief, anger, bitterness, and preoccupation often associated with distressing intense thoughts such as yearning and longing for the deceased [24], [25], [26], [27], [28], [29], [30]. Stressful life events can be broadly categorized as (1) those that entail exposure to a threatening negative life event and (2) those that entail loss of an important positive relationship or situation, physical functioning, social and economical status. Our spectrum instrument includes lifetime exposure to both kinds of potentially damaging events, either of which may be associated with enduring symptoms.
The psychometric properties of the SCI-TALS have been reported elsewhere [14]. Here we briefly summarize our findings. In our original validation study, conducted on a sample (N = 140) of patients with PTSD (n = 48), CG (n = 44) and of healthy control subjects (n = 48), we demonstrated that mean symptoms domains and total scores were significantly higher in patients, nearly all t tests being significant at P < .001. Moreover, the 2 patient groups scored significantly higher than controls on all domains but did not differ from each other in the 6 symptom domains, thereby supporting the content validity of the instrument. Participants with CG endorsed fewer traumatic events than patients with PTSD and more than controls. The internal consistency (Kuder-Richardson coefficient) [31] of all domains, with the only exception of domain I, III, and IX (to which Kuder-Richardson was not applicable as they consist of checklists), exceeded the minimum standard of 0.50 suggested for group comparison by Helmstadter [32].
We have since developed the TALS-SR, a self-report version of the SCI-TALS interview that matches the interview content. The aim of the present study is to report on the reliability of the new self-report questionnaire.
Section snippets
Sample
The study sample included 30 adult out- and inpatients recruited over a 6-month period, with a DSM-IV-TR[2] diagnosis of PTSD, seeking treatment at the Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology of the University of Pisa. Exclusion criteria were neurologic diseases, substance abuse or psychotic symptoms in the month preceding the index assessment, or inability to participate because of the severity of psychiatric symptoms other than PTSD that might compromise the
Subjects
The study sample included 30 patients (54.3% female) with PTSD and 30 healthy control subjects (45.7% female). No significant difference was found between patients and controls on age (45.7 ± 13.5 vs 39.5 ± 11.9, t test = −1.88, P = .065), education level (χ2 = 0.88, P = .347), or occupational status (χ2 = 0.29, P = .589). Patients with PTSD were mostly married or living with a partner (n = 18, 60%), whereas healthy control subjects were mostly single (n = 19, 63.3%).
Mean domain scores for the
Discussion
This study provides evidence for substantial agreement between the self-report and interviewer-based formats for assessment of trauma and loss spectrum. Agreement was excellent for scores on all 9 domains of the instrument and for individual items.
This questionnaire has been developed within the Spectrum Project in a continuing effort to convert interview-based instruments to self-report; we have in fact developed and tested self-report versions of the panic-agoraphobic spectrum [36], the mood
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