Abstract
Interpretive bias refers to the manner in which individuals process and interpret their everyday environment. Some people tend to interpret stimuli in a negative manner, whereas others tend to interpret stimuli more positively. Thus, different individuals may interpret the same situation in vastly different ways, which will, in turn, influence how they feel about the situation. Negative cognitive biases, such as biases of interpretation, have been implicated in the development and maintenance of disorders such as depression and anxiety. Indeed, most interpretive bias research has focused on anxiety and depression, though evidence is accumulating for the effect of interpretive bias on suicidal ideation (Beard et al., 2017; Beevers & Miller, 2004). The primary aim of the present research was to examine the relationship between interpretive bias and suicidal ideation and whether this relationship could be explained by perceived burden and thwarted belonging, two components of the Interpersonal Theory of Suicide (IPTS). It was hypothesised that negative interpretive bias would predict suicidal ideation and that perceived burden and thwarted belonging would mediate the relationship between interpretive bias and suicidal ideation. This mediation hypothesis was expected to be content specific (e.g., that thwarted belonging would mediate the relationship between interpretive bias in belonging scenarios and suicidal ideation). Two additional aims were explored in the present research. Firstly, I aimed to explore the role of the vividness of imagination of scenarios on interpretive bias and suicidal ideation. It was hypothesised that greater vividness would predict suicidal ideation and mediate the relationship between interpretive bias and suicidal ideation. Secondly, I aimed to examine the hypotheses of the IPTS. Hypotheses for this aim largely aligned with the hypotheses of the IPTS, with the exception that it was hypothesised that perceived burden would be a stronger predictor than thwarted belonging.
The present research included three studies, a cross-sectional study, a prospective study, and an intervention study. Across these three studies, high school students and university students completed questionnaires about interpretive bias, perceived burdensomeness and thwarted belonging, and suicidal ideation, and undergraduates engaged in an intervention focused on modifying interpretive bias. Regression, growth modelling, and multilevel modelling were used to examine the relationships among these variables concurrently, prospectively, and following an intervention. There were three primary findings. Firstly, adolescents and young adults with more negative interpretive bias were more likely to report concurrent and prospective passive and active suicidal ideation. Secondly, the relationship between interpretive bias and suicidal ideation was mediated by perceived burden and thwarted belonging. Mediation pathways were found concurrently and prospectively. There was some evidence of a stronger mediation relationship when the bias type and interpersonal factor were congruent (e.g., bias related to burden and perceived burden). However, this congruency was not essential. Thirdly, in Study 3, the effects of a computerised intervention were examined. However, the intervention did not lead to changes in bias, the interpersonal factors, or suicidal ideation. Factors that may have contributed to this null finding are discussed in Chapter 6. Findings for the additional aims regarding imagery vividness and the IPTS were inconsistent and are detailed in Chapters 4-7.
Overall, these findings indicate that interpretive bias may be a risk factor for suicidal ideation. However, further research is needed to examine whether intervention for bias could be beneficial for suicidal ideation. Additionally, further research to explore the roles of methodological factors, such as content specificity and imagery is needed.