Investigating Correlates and Therapeutics of Fatigue

National Institute Of Nursing Research

Investigators

Linked publications & trials

Abstract

Fatigue is a global experience across medical conditions. It is defined as a lack of energy and an overwhelming sense of tiredness that is distinguishable from sadness or weakness. Fatigue is often clustered with other symptoms and behaviors like depression, and has been associated with many medical conditions, including neurological diseases such as Parkinson's disease, autoimmune diseases such Sjogren's syndrome, and have been associated with treatments, such as those who are receiving or who completed cancer treatments. There are also different syndromes where fatigue presents as a main symptom, like chronic fatigue syndrome, fibromyalgia, or those suffering from long COVID. The main cause of fatigue remains poorly understood. Others argue that there is a biologic basis to explain fatigue such as dysregulation of inflammatory response or dysfunction in stress response or even disturbances in the metabolism of nerve cells, or perhaps decreased levels of neurotransmitters such as norepinephrine and serotonin. Other factors to consider when trying to understand fatigue is its relationship with other symptoms like depression. Some studies have shown that the relationship of depression and fatigue may be bidirectional, implying that these conditions may have shared mechanisms. This proposition for a shared mechanism is evidenced by the fact that specific immune markers are associated with both fatigue and depression. Others argue against this shared mechanism hypothesis, as depressive symptoms may improve with pharmacotherapy, while symptoms of fatigue are resistive. Our investigation characterizes the symptoms of fatigue from different clinical populations (cancer patients, patients with fibromyalgia, chronic fatigue syndrome, Sjogren's syndrome, rheumatoid arthritis, Systemic Lupus Erythematosus, and those suffering from long COVID) using standardized questionnaires and determine if physical activity, pain, depression, fatigue catastrophizing, stress, and sleep play a role in their fatigue experience. This study will also examine the potential role of biologic processes such as inflammation and metabolism in fatigue for these individuals. We are also interested in looking at how social determinants of health like their comorbid chronic conditions, their community environment, financial stress from their health conditions, access to healthcare, and climate changes in their location affect their symptom experience. Information collected from this investigation will be useful to improve our understanding of fatigue and identify possible targets to develop therapeutics to alleviate this distressing symptom.