Impaired belief updating and devaluation in adult women with bulimia nervosa

Recent models of bulimia nervosa (BN) propose that binge-purge episodes ultimately become automatic in response to cues and insensitive to negative outcomes. Here, we examined whether women with BN show alterations in instrumental learning and devaluation sensitivity using traditional and computational modeling analyses of behavioral data. Adult women with BN (n = 30) and group-matched healthy controls (n = 31) completed a task in which they first learned stimulus-response-outcome associations. Then, participants were required to repeatedly adjust their responses in a “baseline test”, when different sets of stimuli were explicitly devalued, and in a “slips-of-action test”, when outcomes instead of stimuli were devalued. The BN group showed intact behavioral sensitivity to outcome devaluation during the slips-of-action test, but showed difficulty overriding previously learned stimulus-response associations on the baseline test. Results from a Bayesian learner model indicated that this impaired performance could be accounted for by a slower pace of belief updating when a new set of previously learned responses had to be inhibited (p = 0.036). Worse performance and a slower belief update in the baseline test were each associated with more frequent binge eating (p = 0.012) and purging (p = 0.002). Our findings suggest that BN diagnosis and severity are associated with deficits in flexibly updating beliefs to withhold previously learned responses to cues. Additional research is needed to determine whether this impaired ability to adjust behavior is responsible for maintaining automatic and persistent binge eating and purging in response to internal and environmental cues

Comparative psychopathology of women with bulimia nervosa and obsessive-compulsive disorder

Twenty women with bulimia nervosa (BN) and 20 women with obsessive-compulsive disorder (OCD) were compared on responses to the Minnesota Multiphasic Personality Inventory (MMPI), Symptom Checklist-90-Revised (SCL-90-R), and the Beck Depression Inventory (BDI). Multivariate analyses showed no significant differences between bulimic and OCD women on the MMPI, although a greater number of bulimic women showed significant elevations on several of the clinical scales. Analyses of SCL-90-R profiles indicated higher scores on somatization, interpersonal sensitivity, and psychoticism in the BN sample. Bulimic women did not differ significantly from OCD women on either obsessive-compulsive measures or other measures of anxiety. Similarities and differences in symptom profiles between these two groups are discussed, as well as their implications for alternative treatment approaches for BN

Associations between dimensions of anorexia nervosa and obsessive–compulsive disorder: An examination of personality and psychological factors in patients with anorexia nervosa

Objective: Anorexia nervosa (AN) and obsessive–compulsive disorder (OCD) are highly comorbid. However, the factors that account for this comorbidity are poorly understood. We examined the core dimensions of AN and OCD and psychological and personality factors shared by both disorders. Method: In path analyses (N = 732 women with either current AN or recovered from AN), we examined which factors were uniquely and independently associated with the core dimensions of AN and OCD. We also examined recovery from AN as a moderator. Results: When individuals with AN reported greater concern over mistakes, they endorsed more severity in both AN and OCD core dimensions. These unique associations existed above and beyond all other transdiagnostic personality and psychological factors and regardless of AN recovery status. Conclusions: Concern over mistakes partially accounts for severity in the core dimensions of both AN and OCD. Concern over mistakes may represent an important target in the aetiology of AN and OCD

Cerebrospinal fluid TRH immunoreactivity in anorexia nervosa

Central nervous system (CNS) thyrotropin-releasing hormone (TRH) activity is of interest in patients with anorexia nervosa. First, anorexics have peripheral thyroid abnormalities that appear to be related to weight and nutritional status. Second, CNS TRH activity may effect many other physiologic systems that are known to be disturbed in patients with anorexia nervosa. We found that anorexic patients, when both underweight and studied after attaining goal weight, had significantly reduced CSF TRH concentrations in comparison to controls. These data suggest that weight gain or increased caloric intake, in contrast to its large effect on peripheral thyroid function, has relatively little effect on CNS TRH activity. The reason for reduced CSF TRH in goal weight anorexics is not known but could be trait related, a persistent defect slow to normalize after weight gain, or related to these patients still being at a weight lower than controls. Finally, in terms of CSF TRH concentrations, this study suggests that anorexia nervosa has a different pathophysiology than major depressive disorder