Individual differences in negative affect and weekly variability in binge eating frequency.

OBJECTIVE

To examine the relationship of neuroticism and negative affect (NA) lability with weekly binge eating fluctuations between binge eating disorder (BED) and bulimia nervosa (BN).

METHOD: Individuals with BED (n = 30) and BN (n = 54) from the community completed self-report measures at baseline and prospectively for 12 consecutive weeks. Weekly data were analyzed by using (mean) squared successive deviation to account for fluctuations in NA and binge eating from week to week.

RESULTS

Generalized estimating equations revealed the presence of a two-way interaction between neuroticism and NA lability predicting binge eating fluctuations (Wald χ(2) = 8.25; df = 1; p = .004), indicating that higher NA lability was only related to larger fluctuations in the frequency of binge eating episodes when present in individuals who were also high on neuroticism. An interaction was also detected between eating disorder diagnosis and NA lability, but this was accounted for by differences in average NA between the diagnoses.

DISCUSSION: This study highlights the relevance of two traits and their interaction in understanding individual differences in binge eating fluctuations. Additionally, findings indicate that diagnostic differences in average NA may impact binge eating fluctuations and NA lability.