Association between alexithymia and hypothalamus-pituitary-adrenal axis activity in response to a psychosocial stress in women with eating disorders

Alexithymia is a personality trait that has been defined as a difficulty in identifying, describing, and expressing one's emotions. Individuals with eating disorders (EDs) exhibit higher prevalence of alexithymia than general population. A prolonged exposure to stress related to alexithymia could affect the functioning of the hypothalamus-pituitary-adrenal (HPA) axis. The aim of this study was to assess the reactivity of HPA axis to the Trier Social Stress Test (TSST) by measuring the cortisol response in women with EDs according to their levels of alexithymia. Eighty-nine women with EDs and 40 healthy women participated into an experimental study. Alexithymia was evaluated by the Toronto Alexithymia Scale-20. Salivary cortisol levels were measured to assess the HPA axis reactivity to TSST. Women with EDs and high levels of alexithymia showed higher salivary cortisol compared to women with EDs and low alexithymia levels and healthy controls, but reduced change in cortisol over time, evaluated by AUCi, compared to healthy controls. In conclusion, our study results show that women with EDs and high levels of alexithymia exhibited higher basal activity and an impaired sensitivity of the HPA axis in response to TSST compared to women with EDs and low levels of alexithymia and healthy women.