Symptom science has been a priority for nurse researchers for some time. Both the National Institute for Nursing Research (NINR; Cashion, Gill, Hawes, Henderson, & Saligan, 2016) and leading nurse scientists in the United States and around the world have focused on developing science to help explain, predict, and manage symptoms. Efforts by nurse scientists to advance symptom science include descriptive studies of symptom manifestations in various disease conditions, symptom prevention and treatment interventions, and mechanistic studies designed to discover the underlying biobehavioral processes associated with symptom occurrence and severity (Corwin et al., 2014).
Symptoms, defined as physical or mental characteristics of a condition or disease, are part of individual perception, meaning their occurrence may not be observable to others. Thus, symptoms such as pain and fatigue are typically self-reported. This raises a challenge for those who are studying or providing care for individuals who cannot communicate their symptom experience such as very young children, individuals who are sedated or unable to speak due to their physical condition, and older adults with severe dementia. Consequently, caregivers, professional and personal, often need to observe for physiological or behavioral indicators of symptom expression. Efforts to develop systems that allow caregivers to identify correctly when a symptom is experienced and with what degree of intensity are important to reduce suffering and improve quality of care. Recent research supports the use of caregiver assessment in conjunction with self-reported symptom experience (Mileviciute & Hartley, 2015).
Understanding relationships among symptoms is also important. Symptom cluster research has aided our understanding of the complex nature of many symptoms, which typically do not "travel alone." For example, pain, fatigue, and depressive symptoms often co-occur, particularly in certain health conditions such as cancer. Strategies examining how symptoms cluster together have been promulgated (Miaskowski, 2016), which has led to increased understanding of the symptom experience and particularly the symptom burden associated with severe and/or chronic health conditions.
Understanding the mechanisms underlying symptom occurrence and severity is also of importance in order to develop interventions that prevent or treat symptoms. Much of our understanding of symptom mechanisms come from basic research, including cellular and molecular studies. However, data from basic research need careful interpretation, especially if derived from animal models. Translating animal behavior to human symptom reports can be difficult (Pound & Ritskes-Hoitinga, 2018), but is necessary to provide the basis for mechanism-based interventions for testing in clinical research. Nurse scientists are well trained for this important, translational work, which is needed to alleviate symptom burden.
Theoretical models or theories explaining symptom actions have also been developed (Cashion et al., 2016; Humphreys et al., 2008), which enhance mechanistic discovery as well as understanding of the effects of symptoms on long-term health outcomes, including quality of life. However, these theories and others like them may not explain completely the symptom experience or the mechanisms that contribute to symptom occurrence and severity. Current theoretical models may also fail to provide the needed framework for intervention development, which is greatly needed.
Nursing has claimed symptom science as integral to the discipline and practice of nursing for some years. The NINR has helped move symptom science forward, supporting research that has increased understanding of symptoms and interventions to prevent and treat them. At a workshop for symptom scientists hosted by the NINR 6 years ago, a number of areas for future research were identified, including discovery of biobehavioral underpinnings of symptoms, exploration of symptom precursors including lifestyle factors, development and use of care delivery models and technology to improve symptom management, and discovery of biological indicators of subjective symptoms for use with patients who cannot self-report. I would add to this the need for further study of symptom management interventions with demonstrated effectiveness, perhaps in pragmatic trials.
The extent to which nurse scientists and others have met the challenges of symptom science is unclear. Certainly, there remain many areas where scientific knowledge is lacking. Are nurse scientists prepared to continue the scientific work on science of symptom occurrence, severity, and treatment? Will nurse scientists be able to do this work while maintaining a focus on the unique perspective of those who experience symptoms? Can nurse scientists discover symptom treatments that will be feasible, inexpensive, and effective and that are useful to more than one narrowly focused group of patients? I think nurse scientists are capable of meeting these challenges, as the articles collected in this issue of Nursing Research would indicate. I also think that meeting the challenges of symptom science will continue to require collaboration among scientists, such as that fostered by the work of the NINR and other organizations (Dorsey et al., 2019).
Although not all of nursing science is symptom science, concerns about symptom occurrence, expression, and treatment are undoubtedly integral to nursing. As Florence Nightingale noted 160 years ago, "symptoms or the sufferings generally considered to be inevitable[horizontal ellipsis]are very often not symptoms of the disease at all, but of something quite different" (Nightingale, 2020, p. 1). The work of nurse scientists has helped to reveal the importance of symptoms, no matter their cause, and the need for symptom management if not alleviation. Perhaps in the future, symptoms and "sufferings" will not be inevitable because of the work done today by nurse scientists. That is a challenge worth confronting and one that nursing science is ready to accept.
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