Acute Response of Stress System in Multiple Sclerosis

Background: It has long been suspected that exposure to stress is a major factor that can increase the risk of Multiple Sclerosis (MS) and exacerbate it, as a stress-related disorder. Therefore, we conducted this study to investigate the response of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic-adrenal-medullar (SAM) system to acute social stress. Methods: A total of 46 MS patients and 23 age-sex-matched healthy controls were recruited in the study. The Trier Social Stress Test (TSST) was used to induce acute psychosocial stress. We measured salivary cortisol (SC) to evaluate the HPA axis. In addition, electrocardiography (ECG) was recorded to evaluate the SAM system based on the linear and non-linear features of Heart Rate Variation (HRV). Then, SC and HRV were measured before and after the stress exposure. We also used the Depression Anxiety Stress Scale (DASS) and Emotional Visual Analog Scale (EVAS) to conduct the psychometric assessment and evaluate the perceived stress level, respectively. Results: The mean age of the MS group was 35.38 ± 15 years, with a mean disease duration of 7.4 ± 60. Besides, the HC group's mean age was 35.8 ± 9 years. There were no significant differences in demographic features and DASS scores between the two groups. In response to TSST, both MS and healthy individuals showed a significant increase in the SC levels and EVAS scores, as well as changes in the HRV indices. Notably, significant differences were also found between the two groups regarding the basic and post-stress SC levels, EVAS score, and HRV indices. Unlike the HC group, the SC level returned to its baseline after recovery in the MS group, and the sympathetic tone was more sensitive. Conclusions: Our results indicated that both MS and healthy individuals respond to acute stress regarding neuroendocrine assessment; however, patients with multiple sclerosis show some impairments in this response.