Inhibitory control in bulimic-type eating disorders: a systematic review and meta-analysis

Abstract

The aim of this meta-analysis was to summarise data from neuropsychological studies on inhibitory control to general and disease-salient (i.e., food/eating, body/shape) stimuli in bulimic-type eating disorders (EDs). A systematic literature search was conducted to identify eligible experimental studies. The outcome measures studied included the performance on established inhibitory control tasks in bulimic-type EDs. Effect sizes (Hedges' g) were pooled using random-effects models. For inhibitory control to general stimuli, 24 studies were included with a total of 563 bulimic-type ED patients: 439 had bulimia nervosa (BN), 42 had anorexia nervosa of the binge/purge subtype (AN-b), and 82 had binge eating disorder (BED). With respect to inhibitory control to disease-salient stimuli, 12 studies were included, representing a total of 218 BN patients. A meta-analysis of these studies showed decreased inhibitory control to general stimuli in bulimic-type EDs (g = -0.32). Subgroup analysis revealed impairments with a large effect in the AN-b group (g = -0.91), impairments with a small effect in the BN group (g = -0.26), and a non-significant effect in the BED group (g = -0.16). Greater impairments in inhibitory control were observed in BN patients when confronted with disease-salient stimuli (food/eating: g = -0.67; body/shape: g = -0.61). In conclusion, bulimic-type EDs showed impairments in inhibitory control to general stimuli with a small effect size. There was a significantly larger impairment in inhibitory control to disease salient stimuli observed in BN patients, constituting a medium effect size.

Figure 1. PRISMA Flow Chart.

The flow chart highlights the number of articles found at each stage of the search and the final number of studies that were included in the review; *: the number of studies includes one outlier study; **: four articles reported data for inhibitory control to general stimuli and disease-salient stimuli.

Figure 2. Forest plot for studies on inhibitory control to general stimuli in bulimic-type eating disorders.

▪: bulimia nervosa; ▪ with frame: binge eating disorder; □ anorexia nervosa from the binge/purge subtype; CI95: 95% confidence interval; W %: relative weight (percentage); Favours A/B: lower/higher inhibitory control in bulimic-type EDs than in controls.

Figure 3. Forest plot for studies on inhibitory control to disease-salient stimuli in bulimia nervosa patients.

▪: bulimia nervosa; CI95: 95% confidence interval; W %: relative weight (percentage); food/eating: study used food/eating related stimuli; shape/weight: study used shape/weight related stimuli; Favours A/B: lower/higher inhibitory control in bulimic-type EDs than in controls.