Cognitive biases in military personnel with and without PTSD. Systematic Literature Review

Student thesis: Doctoral ThesisDoctor of Clinical Psychology

Abstract

Background: A number of cognitive biases (memory, attention and judgment) have been implicated in the development and maintenance of PTSD. However, people with PTSD stemming from different sources of trauma may present with different symptom profiles. In particular, military personnel are trained to attend to threat, to assess potential risks in the environment and to make rapid decisions about how to act. Cognitive biases may thus be adaptive in the context of deployment. This review aimed to elucidate the extent to which military personnel with and without PTSD demonstrate cognitive biases. 
Methods: Searches of the databases Embase, PsycINFO, PsycARTICLES, Medline and Web of Science were conducted. Studies were included if they made specific reference to cognitive biases, were conducted in a military population and involved direct measurement of PTSD symptoms. Only studies published in peer-reviewed journals, in English, and since 1980 (when PTSD became a formal diagnosis) were included. Studies were excluded if they focused primarily on genetic, neurobiological or physiological factors, or if participants were under the age of 18 or presented with traumatic brain injury or intellectual disability. Study quality was assessed using a selection of questions from the Quality Assessment Tool for Quantitative Studies and the Research Degrees of Freedom Checklist. 
Results: 21 studies were included for review. The main finding in relation to memory biases was that military personnel with PTSD tend to be overgeneral when describing autobiographical memories. Most studies focused on attentional bias, and generally tended to be of higher quality. Earlier studies involved a modified Stroop task and found that trauma-related words tended to impair performance to a greater extent for those with vs. without PTSD. Later studies used dot-probe paradigms and conceptualised attentional response as a dynamic process, fluctuating between bias towards and away from threat; military personnel with vs. without PTSD demonstrated greater fluctuation. Other studies using visual search tasks and eye-tracking concluded that attentional bias in PTSD is characterised by interference (difficulty disengaging from threat) rather than facilitation (enhanced threat detection). Finally, there was only one study investigating interpretation bias, a form of judgment bias; this found that military personnel with PTSD tended to complete ambiguous sentences with negative rather than neutral endings to a greater extent than those without PTSD. 
Discussion: This review offers a novel contribution to the literature by examining cognitive biases specifically in the context of military PTSD. The relevance for military populations, methodological limitations of the studies and the review, recommendations for future research and implications for clinical practice are considered.
Date of Award1 Oct 2019
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorPatrick Smith (Supervisor)

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