Abstract
Background: The sense of loss of control (LOC) is the key psychological characteristics of bulimia nervosa (BN), and runs throughout the binge-eating and purging behavior. Recent research has shown that LOC may result from impaired goal directed control.
Method: This study examined the relationship between LOC and goal directed control in BN patients. Female patients with BN and healthy controls were enrolled (35 vs 35, age ranged from 17-30). The difference in demographic information, eating disorder scale, mood status, impulsivity, and food addiction scales were compared between the two groups. A sequential two-stage decision task was used to assess goal-directed/habitual control in both groups, and metrics were fitted by computational psychiatry method to assess the goal-directed control. We explored the relationship between LOC and goal directed control using multiple linear regression and partial correlations in BN group. The patients with BN were followed up 1 month after discharge, and the relationship between goal-directed control and treatment outcome which was indicated by LOC reduction rate was analyzed.
Results: BN subjects exhibited impaired goal-directed control, more psychological/behavior characters related to eating disorder, and higher depression, anxiety, impulsivity, food addiction level. BN patients’ higher LOC was associated with goal directed impairment index, eating/weight concern, dietary restriction, BISBAS behavior drive, BIS noplanning impulse and age (p<0.05). However, the influence of goal directed impairment index (choice stickiness and beta MF) on LOC still existed after regressed other factors. The treatment outcome was associated with goal directed impairment index, body shape concern, weight concern, BISBAS behavior drive/fun seeking, BIS noplanning impulse, YFAS. When other factors were regressed and only spaceship task test indicators were considered, a clear trend was observed for higher mixing weight, lower beta MB and choice stickiness (p<0.001) were associated with better treatment outcomes.
Conclusion: We provided evidence on relevant role of goal-directed control deficit in the LOC of BN. The behavioral symptoms of BN are understood from the psychological feature of LOC, and the common potential psychological mechanism of BN and other mental disorders is explored by verifying the role of goal-directed deficits in LOC. These findings provided new insight to improve the interventions of BN. In the future, it may be possible to improve the sense of LOC in BN by intervening with goal-directed deficits.