Introduction Fatigue is a prevalent and potentially debilitating symptom that impacts the health-related quality-of-life of individuals diagnosed with acute and chronic medical conditions. Yet, its etiologic mechanism is not fully understood. Additionally, the assessment and determination of the clinical meaning of fatigue and its multidimensionality may vary by medical condition. Methods A scoping literature review was conducted to investigate how fatigue is defined and measured, including its dimensions, in non-oncologic medical conditions. The PubMed database was searched using keywords. Results Overall, 8376 articles were screened at the title/abstract levels, where 293 articles were chosen for full-text review that mentioned fatigue or included fatigue measures. The review of the full text excluded 246 articles that did not assess at least one fatigue dimension using validated questionnaires and clinical tests. The final set included 47 articles. Physical fatigue was the most assessed fatigue dimension and the Multidimensional Fatigue Inventory was the most widely used questionnaire to assess fatigue in this review. Limitations This review was limited by including only English-language publications and using PubMed as the sole database for the search. Conclusions This review affirms that fatigue is a multidimensional construct, agnostic of medical condition, and that individual fatigue dimensions can be measured by validated clinical measures. Future research should focus on expanding the repertoire of clinical measures to assess specific fatigue dimensions.

Fatigue and anhedonia are commonly reported, co-occurring clinical symptoms associated with chronic illnesses. Fatigue is a multidimensional construct that is defined as a distressing, persistent, subjective sense of physical, cognitive, or emotional tiredness that interferes with usual functioning. Anhedonia is a component of depressive disorders and other psychiatric conditions, such as schizophrenia, and is defined by the reduced ability to experience pleasure. Both symptoms greatly affect the health-related quality of life of patients with chronic illnesses. Although fatigue and anhedonia are commonly associated with each other, understanding the differences between the two constructs is necessary for diagnosis and clinical treatment. A scoping review was conducted based on published guidance, starting with a comprehensive search of existing literature to understand the similarities and differences between fatigue and anhedonia. An initial search of PubMed using fatigue and anhedonia as medical subject headings yielded a total of 5254 articles. A complete full-text review of the final 21 articles was conducted to find articles that treated both constructs similarly and articles that presented fatigue and anhedonia as distinct constructs. About 60% of the reviewed articles consider both constructs as distinct, but a considerable number of the reviewed articles found these constructs indistinguishable. Nomenclature and biology were two themes from the reviewed articles supporting the idea that anhedonia and fatigue are indistinguishable constructs. The information generated from this review is clinically relevant to optimize the management of fatigue related to anhedonia from other fatigue subtypes.

Background/Purpose: Mindfulness-based interventions (MBIs) have been used in medically unexplained symptoms (MUS). This systematic review describes the literature investigating the general effect of MBIs on MUS and identifies the effects of specific MBIs on specific MUS conditions. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis Guidelines (PRISMA) and the modified Oxford Quality Scoring System (Jadad score) were applied to the review, yielding an initial 1,556 articles. The search engines included PubMed, ScienceDirect, Web of Science, Scopus, EMBASE, and PsychINFO using the search terms: mindfulness, or mediations, or mindful or MBCT or MBSR and medically unexplained symptoms or MUS or Fibromyalgia or FMS. A total of 24 articles were included in the final systematic review. Results/Conclusions: MBIs showed large effects on: symptom severity (d = 0.82), pain intensity (d =0.79), depression (d = 0.62), and anxiety (d = 0.67). A manualized MBI that applies the four fundamental elements present in all types of interventions were critical to efficacy. These elements were psycho-education sessions specific to better understand the medical symptoms, the practice of awareness, the nonjudgmental observance of the experience in the moment, and the compassion to ones’ self. The effectiveness of different mindfulness interventions necessitates giving attention to improve the gaps that were identified related to home-based practice monitoring, competency training of mindfulness teachers, and sound psychometric properties to measure the mindfulness practice.