Table 1.

Outlining FSSs, symptoms, diagnosis, common co-morbidities, or clinical overlap.

Functional Somatic Syndrome	Symptoms	Diagnosis	Medical Subspecialty	Clinical Overlap
Fibromyalgia	Chronic widespread muscular pain, hyperalgesia, allodynia, sleep disturbances, physical exhaustion, GI problems, and cognitive difficulties [15]	18 tender points, chronic pain, widespread symptoms [16]	Rheumatology	MDD [17], anxiety, IBS [4], rheumatism [15], IC [16], TMD [18]
IBS	Changes in bowel habit, somatization [19]	Pain relief after defecation, bloating and distention, cramping, nausea [20]	Gastroenterology	Functional dyspepsia [21]
CFS/ME	Severe and disabling fatigue, sleep disruption, unrefreshing sleep, PEM, tender lymph nodes, palpitations, multifocal pain, hyperalgesia, GI problems, and cognitive dysfunction [22]	Longstanding unexplained fatigue, PEM, chronic myalgia and cognitive impairment [23]	Infectious disease [9]	FM, POTS [24], IBS [25], TMD, IC, Raynaud’s disease, thyroiditis [26], depression, mood and anxiety disorders [27]
Tension headaches	Chronic dull, aching, pressure-like head pain [28]	Bilateral, tightening and oppressive headache, mild to moderate pain [29]	Neurology	TMD, FM, sleep disturbances, anxiety, and depression [30]
TMJ dysfunction	Chronic pain in masticatory muscles and TMJs, headache, ear pain, disturbances in jaw movements, facial pain, neck and shoulder tenderness [31]	Jaw movement limitation, irregular TMJ noises (clicking, popping, grating, crepitus), diagnostic imaging (radiography, CT scan, MRI) [32]	Musculoskeletal	TTH, cluster headache, migraine [33]
Vulvodynia	Burning, stinging, or throbbing vulvar pain, dyspareunia [34]	Chronic idiopathic vulvar pain, cotton swab test (check for trigger points) [35]	Gynaecology	FM, IBS, CFS/ME, IC, endometriosis [36]
Interstitial cystitis	Bladder and pelvic pain, frequent, urgent, and painful urination, dyspareunia [37]	Reoccurring idiopathic pain in bladder, pelvis, and perineal area. Pressure/discomfort such as bladder fills, relief after urination. Cystoscopy [38]	Gynaecology, urogynaecology	IBS, FM, CFS/ME, endometriosis, vulvodynia, Sjogren’s syndrome, anxiety disorders [39]

Abbreviations: MDD—Major Depressive Disorder, IBS—Irritable Bowel Syndrome, TMD—Temporomandibular Joint Disorder, IC—interstitial cystitis, CFS/ME—Chronic Fatigue Syndrome/Myalgic Encephalomyelitis, PEM—Post-Exertional Malaise, FM—Fibromyalgia, POTS—Post-Orthostatic Tachycardia Syndrome, TMJ—Temporomandibular Joint, TTH—Tension-type headache.