Identification of children's threat-related interpretation bias following trauma and the evaluation of a cognitive bias training intervention

Author: Susan Hogan

Hogan, Susan, 2019 Identification of children's threat-related interpretation bias following trauma and the evaluation of a cognitive bias training intervention, Flinders University, College of Education, Psychology and Social Work

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A bias to negatively interpret information is common to many childhood mental health problems including posttraumatic stress. A typical example is when an individual automatically interprets ambiguity in a negative and/or threatening way. Understanding these biases is fundamental to cognitive treatment interventions. However, it is unclear to what extent children from non-clinical populations exhibit this interpretation bias style following exposure to a stressful or traumatic event, whether its presence increases the risk of children developing psychological problems, and whether brief interpretive bias training is effective in trauma exposed children. My PhD examined these three issues. Study 1 was conducted given current self-report measures of beliefs broadly assess trauma-related cognition but do not specifically capture dysfunctional interpretation biases. A measure was designed to index children’s negative threat-related interpretive bias style (the Test of Interpretive Bias; TIB). Children (N= 178) aged 9 to 14 years were recruited from schools and completed interpretive bias and outcome measures of trauma and mood symptoms on three occasions: at baseline, and 2- and 12-weeks after the two-week assessment. As predicted, interpretive biases were associated with outcome measures indexing posttraumatic stress, general anxiety and depressive symptoms (rs from .38 – .46). Negative threat-related interpretive biases accounted for a small but significant proportion of trauma-related symptoms (approximately 8%) although the TIB measure was not able to accurately predict individuals at risk of later psychopathology.

As highlighted in the thesis, threat-related interpretation biases have been linked to posttraumatic stress. Study 2 examined the efficacy of a brief bias training intervention delivered in a school setting. Cognitive Bias Modification of Interpretations (CBM-I) is a training procedure previously used to alter negative interpretations and symptoms in children, typically with a focus on social or general anxiety symptoms. I assessed the effectiveness of CBM-I to facilitate an adaptive interpretation style in an unselected sample of children previously exposed to a stressful and/or traumatic event. Potential moderators (e.g., age and gender) and intervention effects were examined over time. Children (N=396) aged 9 to 14 years were randomly allocated to the CBM-I benign or neutral control conditions and completed interpretation bias and outcome symptom measures on four occasions (baseline, 2 weeks post-intervention, and again at 12- and 24-week follow up). Four training sessions were conducted during the two-week intervention. Negative threat-related interpretation biases were correlated with trauma, maladaptive cognition and mood symptoms. CBM-I modified social interpretation biases in the intervention group relative to controls. Treatment effects were observed on children’s anxiety symptoms but not on the trauma-related and depression outcome measures. Excluding two exceptions, age and gender did not moderate intervention outcome. Whole sample analyses showed age moderated training effects on anxiety. Younger children regardless of group, reported a decline in anxiety symptoms, whereas older children who received the CBM-I performed better than same aged controls. Further, gender moderated children’s social interpretation bias outcomes for children above the clinical threshold; specifically, girls in the CBM-I group showed a greater reduction of negative bias in response to ambiguous social situations than control girls, whereas boys in both groups showed reductions at comparable rates. Contrary to predictions, CBM-I did not safeguard children at risk of later psychopathology. That is, children showing elevated interpretative bias at baseline but not yet elevated symptoms who received benign CBM-I training demonstrated comparable rates of developing elevated symptoms at follow-up as controls. A short-term effect of CBM-I was documented in that improved state mood was observed immediately following training in the benign CBM-I group whereas no such effect was seen in controls.

Studies 1 and 2 were conducted with nonclinical samples. Following trauma exposure some children may experience posttraumatic stress disorder (PTSD). Negative and threat-related appraisals/interpretations of the trauma event and aftermath are implicated in the onset and maintenance of PTSD. Cognitive Bias Modification of Interpretations (CBM-I) has yet to be tested in children with clinical levels of PTSD following recent trauma exposure. Study 3, a pilot study, examined the effectiveness of CBM-I to influence children’s cognitive biases and trauma symptoms following accidental injury. Participants (N=17) aged 8-13 years were randomised to a CBM-I positive training or waitlist condition. They completed measures of biases, trauma and mood symptoms on three occasions; baseline, 2 weeks post intervention and at 6-week follow-up. Three online CBM-I training sessions were completed at home over one week. Only six CBM-I participants and one control participant completed the study fully. Single case analyses showed three of the six CBM-I participants showed improvement in their level of negative interpretation bias. Three intervention participants reported improvement in trauma-related symptoms by follow-up. Improvement was also observed for one of the three participants with elevated anxiety at follow-up. Floor effects on some measures and substantial attrition precluded firm conclusions of the efficacy of the intervention. The thesis concludes with a discussion of the wider implications of this program of research.

Keywords: children, trauma, negative interpretation bias, identification of threat-related cognition, cognitive bias modification,

Subject: Psychology thesis

Thesis type: Doctor of Philosophy
Completed: 2019
School: College of Education, Psychology and Social Work
Supervisor: Professor Reg Nixon