Factor structure of posttraumatic stress disorder as measured by the Impact of Event Scale–Revised: Stability across cultures and time.

Abstract

This study examined the structure of posttraumatic stress disorder (PTSD) as measured by the Impact of Event Scale-Revised (IES-R; Weiss & Marmar, 1997), tested factorial invariance for samples of 235 Israeli emergency room patients and 306 U.S. undergraduate students, and then evaluated factorial invariance over multiple occasions within the emergency room sample. A four-factor structure representing intrusion, avoidance-numbing, hyperarousal, and sleep emerged as the preferred model. Configural invariance over groups was supported for this model. Likewise, configural invariance over occasions was demonstrated, but metric invariance was not fully supported, with variation in the loadings on the intrusion factor over time seemingly the source of misfit. Interpretations and conclusions center on sleep as a separate factor underlying the structure of the IES-R, the distinction between avoidance and numbing as a function of how the IES-R (vs. the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) operationalizes the numbing feature of PTSD and possible shifts in the meaning of intrusion over time.

Properties of Swedish posttraumatic stress measures after a disaster

“…Available studies of longitudinal invariance have found support for strong invariance when assessing chronic PTSD, while the overall pattern suggests weaker forms of invariance when assessments were less distant from the event (King et al, 2009;Krause et al, 2007;M. Wang et al, 2012).…”

“…Note that nearly all confirmatory factor analyses (CFAs) have used measures mapping directly onto the DSM-IV symptom criteria. If a model can provide good fit also when applied to other PTSD measures it would strengthen the evidence and could prevent that the refinement process ends prematurely (King et al, 2009). …”

“…The few studies that exist suggest that at least configural invariance seems plausible, but more research is needed (King et al, 2009;Krause, Kaltman, Goodman, & Dutton, 2007;M. Wang, Elhai, Dai, & Yao, 2012).…”

Testing the dimensionality of posttraumatic stress responses in young Chinese adult earthquake survivors: further evidence for “dysphoric arousal” as a unique PTSD construct

“…[10,11,18] Among studies directly comparing the two models, mixed results have been found. Some studies found support for the numbing model of King et al [16,[19][20][21][22][23][24][25] whereas others found support for the dyphoria model of Simms et al [26][27][28][29][30][31][32] Recently, Yufik and Simms conducted a meta-analysis of 40 previous PTSD studies, and found that although the four-factor models both yielded good model fit across subamples of studies, the dyphoria model appeared to provide a superior fit to the numbing model across studies.…”

Measurement Invariance of Ryff’s Psychological Well-being Scales Across Italian and Belarusian Students

“…Over the years, an extensive body of studies has been carried out, covering different domains such as psychological features (Benson et al 2010;Fan et al 2008;Hofer et al 1997;Nye et al 2008), psychopathology (Ang et al 2009;Byrne et al 1995;Feaster et al 2010;Hill and Hughes 2007;King et al 2009;Wang et al 2010), and different aspects of health and well-being (Erhart et al 2009;Robitschek and Keyes 2009;Shevlin and Adamson 2005;Shevlin et al 1998;Wu and Yao 2006). Similar studies are currently not available as far as the PWB Scales are concerned, even though the instrument is widely applied in different socio-cultural and linguistic contexts.…”