Latent Change Trajectories in Mood During Focused CBT Enhanced for Eating Disorders Are Associated With Global Eating Pathology at Posttreatment and Follow-Up Among Individuals With Bulimia Nervosa Spectrum Disorders: A Preliminary Examination.

Bulimia nervosa (BN) is characterized by recurrent loss of control over eating (LOC) and inappropriate compensatory behaviors. Although cognitive-behavioral therapy (CBT) is efficacious for BN, many patients continue to experience symptoms at posttreatment. One potential driver of this low treatment response may be low mood, which maintains BN symptoms through negative reinforcement. Thus, it is important to understand how mood changes over enhanced cognitive-behavioral therapy (CBT-E) and whether these changes are associated with improved treatment outcomes. Participants (N = 56) with BN-spectrum eating disorders (EDs) received 16 sessions of the focused version of CBT-E. The Eating Disorder Examination (EDE) was used to measure ED symptoms (global ED pathology, frequency of binge episodes, and compensatory behaviors) at pre- and posttreatment. Latent growth mixture modeling (LGMM) of affective ratings via digital self-monitoring identified latent growth classes. Kruskal-Wallis H tests examined the effect of trajectory of change in mood on pre- to posttreatment symptom change. LGMM yielded a four-class model that best fit the data representing distinct mood trajectories over the course of treatment: (a) highest baseline mood, linear improving; (b) moderate baseline mood, stable; (c) moderate baseline mood, quadratic worsening; and (d) lowest baseline mood, quadratic improving. Participants who demonstrated worsening mood over treatment (i.e., individuals in the "moderate baseline mood, quadratic worsening" class) had significantly higher EDE global scores at posttreatment and follow-up compared to participants with stable mood across treatment. Change in LOC eating frequency and compensatory behaviors across treatment did not significantly differ by mood class. The main effect of mood class or interaction effect between time and mood class on objective binge episodes, subjective binge episodes, and compensatory behaviors was not significant. There were no significant differences in global ED pathology at either posttreatment or follow-up for any other class comparisons. These results suggest that certain trajectories of change in mood during treatment are particularly associated with change in pre- to posttreatment EDE global score. If replicated, our findings could suggest that future iterations of CBT-E should target mood early in treatment in order to maximize reductions in global eating pathology.