Exposure to trauma is common; however not everyone develops posttraumatic stress disorder (PTSD) or depression after a traumatic event. Prior trauma in childhood trauma has been linked with several detrimental outcomes in adulthood. This thesis aims to explore the vulnerability of adults with a history of childhood trauma to psychopathology following exposure to a subsequent trauma. The thesis begins with a review of the relevant literature, including a discussion of prevalence of trauma, the impact of trauma, a presentation of cognitive models of PTSD and evidence for them, a discussion of risk factors for development of PTSD and depression, and the impact of trauma in children in light of developmental theories and research evidence. The thesis then presents the findings of two studies focusing on the vulnerabilities of childhood trauma. The first study addresses whether individuals with a history of childhood trauma are at an increased risk of developing PTSD or depression after a subsequent trauma in adulthood. It further assesses the contribution of other vulnerability factors frequently linked to childhood trauma to this risk, such as frequency of prior trauma, prior social support or prior psychopathology. The results showed that adults with a history of childhood trauma were more likely to experience posttraumatic stress and depressive symptoms after a subsequent trauma compared to adults with adolescent trauma, adulthood trauma only or no trauma history. The results further showed that those with childhood trauma experienced a greater number of prior traumas, had received less social support prior to the trauma and had more prior psychopathology compared to the other groups. Findings indicated that this group’s increased risk of psychopathology after a subsequent trauma was predominantly through these vulnerability factors. The second study used structural equation modelling (SEM) to investigate the PTSD symptom response pathways to PTSD in those with a history of childhood trauma and those without a history of childhood trauma to compare if they differ. Two distinct PTSD subtypes have recently been suggested: a dissociative/avoidant and a re-experiencing/arousal subtype. This study investigated whether these subtypes represent response pathways after a trauma, and whether these response pathways differ between adult trauma survivors with and without a history of child trauma. Results showed that individuals with a history of childhood trauma utilise a predominantly avoidant response leading to PTSD, while those without childhood trauma utilise a predominantly arousal and re-experiencing response. Finally, these results and their implications are discussed.
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