|dc.description.abstract||Body dysmorphic disorder (BDD) is not uncommon, frequently onsets in early to late adolescence (from age 12 to 16 years), and is associated with severe impairments. Despite its prevalence and impact, current evidence suggests that BDD frequently goes undiagnosed. Building upon the existing theory and research, and recent changes to the diagnostic description and classification of BDD, the primary purpose of the current studies was to develop a new measure to assess BDD symptoms in adolescents and to examine risk and protective factors associated with BDD symptoms. This thesis consists of a series of three empirical studies, which have been published (Studies 1 and 2) or prepared for submission (Study 3) for publication. The first two studies were designed to advance science and practice related to the assessment of adolescent BDD symptoms, while the third study focused on the identification of risk and protective factors for emerging BDD symptoms among adolescents.
In Study 1, the factor structure and validity of a widely used measure of body dysmorphic symptoms, the Appearance Anxiety Inventory (AAI; Veale et al., 2013) was investigated. The participants were Australian university students (N = 730) and Australian adolescents (N = 862) who completed surveys. Findings from the exploratory analysis with 50% (n = 365) of the university students supported a 1-factor solution with nine items. Confirmatory factor analysis with the remaining university student (n = 365) and the adolescent samples demonstrated the proposed 1-factor model had an adequate fit to the data on most indicators. It was concluded that the AAI is best considered as a single factor scale with 9 of the original 10 items when used with general, community samples of young adults or adolescents.
Based on a review of existing measures of BDD for adolescents and consideration of the DSM-5 criteria for BDD, Study 2 involved the development of a new self-report measure to assess BDD symptoms in adolescents. The new measure, the Multidimensional Youth Body Dysmorphic Inventory (MY BODI), was developed to assess BDD symptoms across all domains of DSM-5 diagnostic criteria and uses a unique response set with the aim of reducing socially desirable responding. Following expert review and piloting of items, results from an exploratory factor analysis with data collected from 582 Australian secondary school students (55% female; Mage = 13.62 years) supported a 3-factor, 21-item measure, with excellent validity. The three factors conformed to the DSM-5 diagnostic criteria of Impairment/Avoidance, Preoccupation/Repetitive behaviours, and Insight/Distress. Supporting the convergent validity of the measure, the MY BODI total score and subscale scores correlated with other measures of BDD symptoms, including the AAI and BDDQ.
Finally, in Study 3, the aims were to test whether dispositional mindfulness and self-compassion protect against the negative impact of peer appearance teasing on BDD symptoms. Participants were 170 Australian high school students (59% female; Mage = 15.44 years) who completed the MY BODI, and measures assessing peer teasing about appearance, five facets of dispositional mindfulness, self-compassion, and self-judgment. In hierarchical regressions, peer teasing was associated with reporting more total BDD symptoms, and two components of mindfulness (describing and non-judgment) and self-compassion were uniquely associated with adolescents’ reports of fewer total BDD symptoms. One factor of mindfulness, observing, was associated with more reported BDD symptoms. In moderation analyses, the association between peer appearance teasing and BDD symptoms was stronger when mindful describing was high relative to low, and when self-judgment was low relative to high. Findings were similar across all subscales of MY BODI. These findings suggest that mindfulness and self-compassion are generally associated with fewer BDD symptoms (with the exception of mindful observing). However, in contrast with the hypothesised protective effects, adolescents who reported a greater ability to mindfully describe their experience and those who were less self-judging were more negatively affected by peer appearance teasing.
In summary, the results of this thesis support using a 9-item AAI measure with adolescents, provide a new multidimensional measure of BDD that appears reliable and valid, and advance the study of how social and individual factors should be considered in combination in order to explain when adolescents are at more risk for elevated BDD symptoms. BDD is a complex and debilitating disorder that tends to onset in adolescence and runs a chronic course, thus making this an important problem to study in children and adolescents.||