Multiple levels assessment of the RDoC "system for social process" in Eating Disorders: Biological, emotional and cognitive responses to the Trier Social Stress Test

Background: Social dysfunction is a putative risk and maintaining factor for Eating Disorders (EDs). We assessed biological, emotional, and cognitive responses to a psychosocial stressor, in order to provide a multilevel investigation of the RDoC social process system in EDs. Methods: Patients were recruited among those seeking treatment for an ED. Cortisol response to Trier Social Stress Test (TSST) was measured in 105 subjects: 35 women with anorexia nervosa (AN), 32 with bulimia nervosa (BN) and 38 healthy women. Anxiety, hunger, and desire to eat throughout TSST were rated in a subgroup of them (23 AN, 21 BN, and 25 control women). Two-way ANOVAs with repeated measures were run to assess differences among groups. Results: The TSST-induced cortisol secretion of AN women was significantly higher than in BN and healthy women; this significance disappeared after controlling for body mass index. Compared to healthy women, both AN and BN women showed reduced cortisol reactivity that disappeared after controlling for trait anxiety and ineffectiveness. Both ED groups displayed increased anxiety response to TSST, while only AN group reported greater decreases in hunger and desire to eat. No significant correlations were found between cortisol and anxiety, hunger, or desire to eat in response to TSST. Conclusions: People with EDs are characterized by blunted cortisol reactivity and greater anxiety, hunger, and desire to eat responses to a psychosocial stressor without any significant association between these measures. This study provides the first empirical and multilevel support to a deranged functioning of the RDoC "system for social process" in EDs.