Myalgic Encephalomyelitis/chronic fatigue syndrome: a critical narrative review of modern concepts and unani perspectives.

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic, disabling, multisystem illness characterized by persistent fatigue, post-exertional malaise/post-exertional symptom exacerbation (PEM/PESE), unrefreshing sleep, and cognitive impairment. Classical Unani medicine does not recognize ME/CFS as a distinct disease entity. However, its descriptions of fatigue (I'yā), particularly I'yā Dhātī (spontaneous fatigue), provide a basis for examining parallels with ME/CFS.

OBJECTIVE

To examine I'yā Dhātī (spontaneous fatigue) and its three simple subtypes (I'yā Qarūḥī, I'yā Tamaddudī, and I'yā Waramī) and compare them qualitatively with contemporary ME/CFS, including areas of similarity and discordance.

METHODS

This critical narrative review used structured searches of PubMed, Scopus, Google Scholar, ScienceDirect, and Web of Science. Eight primary Unani sources were examined: Al-Qānūn fi al-Ṭibb, Kulliyāt al-Qānūn, Kitāb al-Ḥāwī, Kitāb al-Murshid, Kitāb al-Manṣūrī, Dhakhīrah-i Khwārazm Shāhī, Kitāb al-Kulliyāt, and Al-Mukhtārāt fi al-Ṭibb. The three subtypes were compared using predefined qualitative domains based on contemporary ME/CFS features and classical descriptions.

RESULTS

I'yā Tamaddudī (distensive fatigue) showed the greatest phenomenological overlap with ME/CFS, particularly spontaneous fatigue, generalized heaviness, sleep disturbances, mental dullness, reduced functional capacity, and diffuse somatic manifestations. However, no clearly documented classical equivalent of delayed PEM/PESE was identified, representing a major area of discordance.

CONCLUSION

I'yā Tamaddudī (distensive fatigue) showed the greatest phenomenological/conceptual overlap with ME/CFS among the subtypes examined. This represents a historical and interpretative correspondence, not biological, diagnostic, or therapeutic equivalence. Independent operationalization and prospective evaluation are required before its clinical or biological relevance can be established.