Somatic Symptom Disorder in Taiwan: Integrating Psychopathology, Neurobiology, and Health Policy Perspectives

Abstract
Somatic symptom disorder (SSD), formally introduced in the DSM-5 in 2013, marked a paradigm shift from exclusion-based (“medically unexplained”) to inclusion-based (“excessive distress”) diagnostic criteria. As a diagnosis with explicit positive criteria, SSD provides a framework to empirically investigate hypotheses on cultural expressions of emotional distress—such as the lower observed prevalence of depression in East Asia and the prominence of somatic complaints.
Over the past decade, our research team has systematically investigated SSD across epidemiological, neurobiological, and clinical domains. A nationwide survey using computer-assisted telephone interviews yielded Asia’s first community prevalence estimate for SSD at 5%, comparable to Western populations. SSD was the strongest predictor of healthcare utilization, independent of comorbid anxiety or depression. Latent class and cluster analyses identify symptom-based subtypes with distinct psychopathological profiles, such as demoralization and health-related anxiety.
Functionally, SSD and major depressive disorder independently contributed to impaired quality of life across physical, psychological, and social domains. Depression remained the dominant factor associated with functional decline, though SSD-related cognitive and somatic concerns also played significant roles. Neuropsychological assessments (CANTAB, Stroop tasks) revealed deficits in selective attention and negative emotion processing. Physiological studies highlighted sex-specific autonomic dysregulation, with cue-specific heart rate variability (HRV) providing diagnostic differentiation in women.
Integrating the Diagnostic Criteria for Psychosomatic Research-Revised (DCPR-R) with DSM-5 improved diagnostic precision and clinical utility. Constructs such as demoralization, irritable mood, and health anxiety enhanced the stratification of treatment needs. These findings underscore the need for a dimensional and biopsychosocial framework for understanding and managing SSD within both clinical and policy domains.