Bulimia nervosa

Bulimia Nervosa (BN) includes episodes of binge eating followed by reccurent inappropriate behaviours (such as self-induced vomiting) for preventing weight gain from the caloric overload. To satisfy the current Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) (2000) criteria, the behavior must be frequent (on average, at least two times per week for 3 months or longer). BN developed in majority of AN patients in progress of time.

In addition to binge eating and purging, individuals with BN frequently report concurrent psychological symptoms such as depression, anxiety, low self-esteem, and cognitive eating disorder pathology (e.g., weight and shape concerns) at more severe levels than non-psychiatric controls. Psychological theories suggest that concurrent psychological syptoms are very effective in both the development and maintenance of blumic pathology. In addition, certain psychological symptoms (e.g., greater depressive symptoms and lower self-esteem) may lead to poorer treatment outcomes for adults with BN.

In a study, fixed sized meal were given to individuals with BN  and controls. They are wanted to evaluate their subjective satiety. Indivıiduals with BN reported that they are feeling less full when compared with controls. Furthermore, a potential biological mechanism was identified in BN. This mechanism is associated with cholecystokinin (CCK) which have role in controlling food intake. CCK has an important role in the termination of meal with its post-prandial increasement. The release of  CCK was diminished after a meal in individuals with BN, but not in the control group. This study demonstrated a potential translational link between a biological control mechanism from the gut and clinical symptoms, suggesting that postingestive satiety signals are disturbed in BN. The change in fullness per unit of food consumed was much lower in the individuals with BN, consistent with a disturbance in the development of satiety.

In another study,  the quantity of consumed food and the total amount to be provided were not indicated to participants while they ate showed various results. In contrats to the previous study, the average ratings of fulness of the individuals with BN during the course of the meal were identical to the those of controls. In contrast to the previous study where study participants determined how much they ate and were aware of the quantity of what they had eaten during the course of the meal. According to the results of this study,  the change in fullness per unit of food consumed was quite normal, and therefore did not suggest an impairment in the development of satiety. Notably, in the previous study, subjects were asked specifically to binge eat, suggesting the possibility that a person’s decision to overeat then alters their how they interpret subjective sensations and biological signals resulting from food ingestion.