Exploring psychological mechanisms that contribute to the development of post-traumatic stress disorder in mild traumatic brain injury : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University, Wellington, New Zealand

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Massey University
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Mild traumatic brain injuries (mTBI) are prevalent. Contrary to previous beliefs, a significant portion of individuals experience persistent post-concussion symptoms. Psychological mechanisms have been found to increase pathologies such as post-traumatic stress disorder (PTSD) and affect functional status within a large spectrum of health disorders. Alas, they have not been vastly explored within an mTBI population. This study examined the role of psychological flexibility and fear avoidance in the development of PTSD post-mTBI. Method: 169 participants were recruited from a specialist concussion service and completed a range of self-report measures within one month of entry. The psychological mechanisms were ascertained. This included psychological flexibility (Acceptance and Action Questionnaire in Acquired Brain Injury (AAQ-ABI(RA)) and fear avoidance (Fear Avoidance Behaviour after Traumatic Brain Injury Questionnaire (FAB-TBI)). In addition, measures of, psychological distress (Depression Anxiety and Stress Scale, DASS-21), post-traumatic stress disorder symptoms (PTSS) (Impact of Events Scale-Revised (IES-R)), post-concussion symptoms (PCS) (Rivermead Post-Concussion Questionnaire, (RPQ)), and functional disability (Word Health Organisation Disability Assessment Schedule 2.0 WHODAS 2.0) were gathered. Results: A large positive correlation was found between PTSS, PCS and functional disability. Linear regression analysis revealed that psychological flexibility and fear avoidance made a unique and significant contribution to PTSS in mTBI, even when controlling for confounding variables. Mediation analysis revealed an indirect effect of PTSS on PCS and functional status through both psychological mechanisms. Multiple mediation indicated that psychological flexibility was significantly associated with PCS, but fear avoidance was not. Whereas both were associated with functional status. Conclusion: PTSS significantly contribute to mTBI outcomes (i.e., PCS, functional status). Psychological flexibility and fear avoidance contribute to the development of PTSS following mTBI and affect recovery. These findings suggest that psychological flexibility and fear avoidance should be targeted in treatment interventions for mTBI.
mild traumatic brain injury, post-traumatic stress disorder, post-traumatic stress symptoms, psychological flexibility, fear avoidance, outcomes, post-concussion symptoms, functional status