Psychosomatic symptoms related to exacerbation of fatigue in patients with medically unexplained symptoms

Medically unexplained symptoms (MUS) are common conditions that cause various somatic complaints and are often avoided in primary care. Fatigue frequently occurs in patients with MUS. However, the somatic and psychiatric symptoms associated with fatigue in patients with MUS are unknown. This study aimed to clarify the intensity of fatigue and the related somatic and psychiatric symptoms in patients with MUS.

A total of 120 patients with MUS aged 20-64 years who visited the Department of Psychosomatic Medicine, Toho University Medical Center Omori Hospital, between January and March 2021 were considered. The participants' medical conditions were assessed using the Chalder Fatigue Scale (CFS), Somatic Symptom Scale-8 (SSS-8), and Hospital Anxiety and Depression Scale (HADS). We estimated the relationship between CFS, SSS-8 and HADS by using Spearman's rank correlation. Additionally, linear multiple regression analysis with CFS as the objective variable was used to identify symptoms related to fatigue.

Fatigue was significantly associated with all symptoms observed (p < 0.01). Linear multiple regression analysis revealed that "dizziness," "headache," and "Sleep medication" were extracted as relevant somatic symptoms (p < 0.05), independent of anxiety and depression, which were already known to be associated with fatigue in MUS.

The intensity of anxiety, depression, headache, and dizziness were all associated with the intensity of fatigue in MUS patients. On the contrary, sleeping medication was associated with lower levels of fatigue in MUS.