Temporal relationships between awakening cortisol and psychosocial variables in inpatients with anorexia nervosa – A time series approach

• We investigated the awakening cortisol of AN patients using a time series design.
• Awakening cortisol of AN patients was elevated as compared to a control group.
• Patients with HSS showed less stable awakening cortisol time series compared to patients with LSS.
• Antipsychotic medication did not change awakening cortisol in a specific way.
• In four patients, higher cortisol values were temporally associated with higher values of depressive feelings.

ObjectiveThe aim of the study was to investigate the characteristics of the awakening salivary cortisol in patients with anorexia nervosa (AN) using a time series design. We included ten AN inpatients, six with a very low BMI (high symptom severity, HSS group) and four patients with less severe symptoms (low symptom severity, LSS group).MethodsPatients collected salivary cortisol daily upon awakening. The number of collected saliva samples varied across patients between n = 65 and n = 229 (due to the different lengths of their inpatient stay). In addition, before retiring, the patients answered questions daily on the handheld regarding disorder-related psychosocial variables. The analysis of cortisol and diary data was conducted by using a time series approach.ResultsTime series showed that the awakening cortisol of the AN patients was elevated as compared to a control group. Cortisol measurements of patients with LSS essentially fluctuated in a stationary manner around a constant mean. The series of patients with HSS were generally less stable; four HSS patients showed a non-stationary cortisol awakening series. Antipsychotic medication did not change awakening cortisol in a specific way. The lagged dependencies between cortisol and depressive feelings became significant for four patients. Here, higher cortisol values were temporally associated with higher values of depressive feelings.ConclusionsUpon awakening, the cortisol of all AN patients was in the standard range but elevated as compared to healthy controls. Patients with HSS appeared to show less stable awakening cortisol time series compared to patients with LSS.