Psychiatry - Theses

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    Understanding the neural basis of the experience of negative moral emotions in healthy and depressed adolescents
    Bastin, Coralie ( 2017)
    Background: Shame and guilt are negative moral emotions that are usually experienced when rules, norms or social agreements are broken. These emotions are associated with punishing feelings of self-blame relating to behaviour and character and are crucial for social development during adolescence. However, there is currently a poor understanding of the neurobiological underpinnings of these emotions. The importance of understanding the neural correlates of these emotions lies in a better understanding of human social functioning and the role they play in particular mental disorders such as depression. Depression is a mood disorder that affects a large number of adolescents. A key component of depression is emotional dysfunction, and it has been recognised that moral emotions such as shame and guilt play an important role in the development and maintenance of depression. Despite extensive knowledge of the neural mechanisms underlying deficits in basic emotional processes in adolescent depression, there is no research to date that has investigated the neural correlates of shame and guilt in a depressed adolescent population. Broad Aim of PhD study: To investigate the common and distinct neural correlates of the experience of negative self-conscious emotions (i.e., shame and guilt) in healthy and depressed adolescents using a novel social moral dilemma paradigm. Methodology: A novel shame and guilt induction paradigm was developed for use with functional Magnetic Resonance Imaging (fMRI). A total of 44 female teenager-relevant social moral dilemmas were created and validated via an online survey. Twenty-two female adolescents with major depressive disorder (MDD) (mean age = 20.19) and 47 healthy female controls (mean age = 18.89) aged 15-24 were recruited from the Melbourne area. Patients were recruited from Orygen Youth Health and Headspace Centres in Melbourne. During fMRI, the adolescents were presented with dilemmas one at a time and were requested to a) make a decision about what they would do if in that situation, and b) reflect upon how they would feel. Ratings of emotional experience were collected post-scan. Analyses were conducted to investigate the neural correlates of self-reported shame and guilt experiences in both depressed and healthy adolescents, and to examine whether the groups differed in their neural response associated with these negative self-blaming emotions. Results: Findings showed marked individual variations in shame and guilt responses to the different dilemmas in both the healthy control and MDD participants. The common experience of shame and guilt in healthy individuals was associated with significant activation in lateral and medial parts of the prefrontal cortex (including the medial and dorsomedial PFC extending to the supplementary motor cortex, the dorsal anterior cingulate cortex and mid-cingulate, the lateral superior, middle and inferior frontal gyri, and the ventrolateral PFC extending to the anterior insula), temporal area (superior temporal sulcus), parietal regions (supramarginal and angular gyri), as well as some subcortical regions (thalamus and caudate nucleus). Adolescents with major depressive disorder showed similar associations between shame and guilt and brain activity compared with healthy participants, but with a lesser extent of activation. In terms of differences between healthy and depressed individuals, the anterior middle temporal cortex was associated with guilt to a greater extent for the control group compared to the patient group. Additionally, results showed activity in the superior parietal cortex extending to the inferior parietal cortex and the precuneus to be associated with shame to a greater extent in patients compared to controls. Significance: The proposed project will advance the understanding of the neural correlates of shame and guilt in healthy individuals as well as the neural basis of these same emotions in depressed adolescents. The information gained from this will be of significant value for the development of prevention and treatment efforts for depression as well as other mental disorders for which these self-conscious emotions play a significant role.