A factor analysis of posttraumatic stress disorder symptoms using data pooled from two venlafaxine extended‐release clinical trials

Dan J Stein,Jonathan R T Davidson,Barbara O Rothbaum,Ronald Pedersen,David S Baldwin,Annette Szumski

doi:10.1002/brb3.183

Abstract

BackgroundConfirmatory factor analysis (CFA) of Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) three-factor posttraumatic stress disorder (PTSD) diagnostic criteria was conducted to determine fit for this patient population. An exploratory factor analysis (EFA) of alternate symptom structures was planned to identify symptoms that cluster in this population. The response of symptom factors to treatment with venlafaxine extended release (ER) was explored.MethodsBaseline 17-item Clinician-Administered PTSD Scale (CAPS-SX17) data were pooled from patients enrolled in two double-blind, randomized, placebo-controlled trials. The CFA was conducted using maximum likelihood and weighted, least-squares factor extraction methods. The EFA was performed using a polychoric correlation covariance matrix and Pearson correlation matrix.ResultsData from a pooled population of 685 patients (venlafaxine ER: n = 339; placebo: n = 346) were analyzed. CFA rejected the DSM-IV three-factor structure. The EFA identified a different three-factor structure as the best fit: factor 1 included reexperiencing symptoms, factor 2 included symptoms of altered mood and cognition, whereas factor 3 comprised avoidance and arousal symptoms. All DSM-IV symptom factors and all factors in the identified three-factor model responded positively to venlafaxine ER treatment.ConclusionsData are consistent with literature failing to confirm the three-factor structure of DSM-IV PTSD, and they support the DSM-5 inclusion of a symptom cluster addressing altered mood and cognition in PTSD. The efficacy of venlafaxine ER in reducing a range of symptom clusters in PTSD is consistent with its multiple mechanisms of action.

Highlights

Posttraumatic stress disorder (PTSD) is characterized by a broad range of symptoms and behaviors stemming from exposure to a traumatic event that is a perceived threat to oneself or others
The Confirmatory factor analysis (CFA) demonstrated a significant lack of fit for the DSM-IV three-factor posttraumatic stress disorder (PTSD) symptom structure in the pooled sample, as well as in the individual trials
The exploratory factor analysis (EFA) suggests a three-factor structure; the first two factors loaded on the same items for both studies and the third factor loaded on different items for each study

Summary

Introduction

Posttraumatic stress disorder (PTSD) is characterized by a broad range of symptoms and behaviors stemming from exposure to a traumatic event that is a perceived threat to oneself or others. The PTSD symptoms described in the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) (American Psychiatric Association 1994) are divided into three clusters: reexperiencing, avoidance/numbing, and hyperarousal. Confirmatory factor analysis (CFA) of Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) three-factor posttraumatic stress disorder (PTSD) diagnostic criteria was conducted to determine fit for this patient population. An exploratory factor analysis (EFA) of alternate symptom structures was planned to identify symptoms that cluster in this population. The EFA identified a different three-factor structure as the best fit: factor 1 included reexperiencing symptoms, factor 2 included symptoms of altered mood and cognition, whereas factor 3 comprised avoidance and arousal symptoms. Conclusions: Data are consistent with literature failing to confirm the three-factor structure of DSM-IV PTSD, and they support the DSM-5 inclusion of a symptom cluster addressing altered mood and cognition in PTSD. The efficacy of venlafaxine ER in reducing a range of symptom clusters in PTSD is consistent with its multiple mechanisms of action

Methods

Results

Discussion

Conclusion