Characterizing and predicting trajectories of disordered eating over adolescence

This study sought to identify distinct trajectory classes of growth of disordered eating (DE), and their respective correlates and risk factors. Females ages 12-19 years (Australian Twin Registry) were interviewed by telephone with the Eating Disorder Examination on 3 occasions (Wave 1: N = 699; Wave 2: N = 669; Wave 3: N = 499). Each participant also completed self-report measures across all waves, and their parents at Waves 1 and 2. Growth mixture modeling determined the optimal classes representing DE growth trajectories over 3 data-points. The best fit was a 3-class solution constituting: (a) no growth in DE over time (90%; low-static) where 10% reported a lifetime eating disorder (ED); (b) a high intercept but decreasing over time (7%; 53% had a lifetime ED; attenuating); (c) an increasing level of DE (3%; 80% experiencing a lifetime ED; escalating). The majority (64%) of EDs in the attenuating group were diagnosed at Wave 1, whereas 84% of EDs in the escalating group were diagnosed at subsequent waves. The low-static group had fewest significant correlates/risk factors for DE. A multivariable GEE identified that over adolescence, internalization of the thin ideal was 2.5 times more likely characterize an escalating rather than low-static DE symptom trajectory. These findings underscore the fundamental importance of concentrating efforts on reducing the potency of the thin ideal message, and strategies directed toward resolving life stressors by effective management of emotion and problem resolution, in order to prevent the development of DE.