Physical complaints not attributable to verifiable, conventionally defined diseases, i.e., medically unexplained or functional somatic symptoms, are prevalent in all medical settings, but their classification is contested as numerous overlapping diagnoses and syndrome labels have been introduced. This study aims to determine whether functional somatic symptoms cluster into distinct syndromes and diagnostic entities.
The 978 consecutively admitted patients from a neurological department (n = 120), a medical department (n = 157), and from primary care (n = 701) were interviewed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) diagnostic instrument.
Patients complained of a median of five functional somatic symptoms; women of six, men of four (p < .0001). No single symptoms stood out as distinctive for patients with multiple symptoms. Principal component factor analysis identified a cardiopulmonary including autonomic (CP), a musculoskeletal (MS), and a gastrointestinal (GI) symptom group explaining 36.9% of the variance. Latent class analysis showed that the symptom groups are likely to materialize in the same patients, suggesting that they are different manifestations of a common latent phenomenon. Inclusion of a group of five additional general, unspecific symptoms in latent class analysis allowed construction of clinical diagnostic criteria for ‘bodily distress disorder’ dividing patients into three classes: nonbodily distress (n = 589), modest bodily distress (n = 329, prevalence 25.3%, men 20.4%, women 25.6%), and severe bodily distress (n = 60, prevalence 3.3%, men 1.2%, women 4.8%).
The study suggests that bodily distress disorder as defined here may unite many of the functional somatic syndromes and some somatoform disorder diagnoses. Bodily distress may be triggered by stress rather than being distinct diseases of noncerebral pathology.
SCAN = Schedules for Clinical Assessment in Neuropsychiatry; CP = cardiopulmonary; MS = musculoskeletal; GI = gastrointestinal; CFS = chronic fatigue syndrome; DSM = Diagnostic and Statistical Manual of Mental Disorders; ICD = International Classification of Diseases; SCL = Symptoms Check List; CAGE = cutting down, annoyance by criticism, guilty feeling, and eye-openers; WHO = World Health Organization; STATA = statistical software; IQR = interquartile range; GS = general symptoms; IBS = irritable bowel syndrome.