Psychosocial and Clinical Correlates of Somatic Symptom Disorder in Patients With and Without Somatic Comorbidities: Cross-sectional Findings from the SOMA.SSD Study

OBJECTIVE: Somatic Symptom Disorder (SSD) is characterized by persistent physical symptoms causing significant distress. Unlike earlier criteria, SSD does not require the absence of other medical conditions, resulting in a heterogeneous patient population. Few studies have systematically compared SSD patients with and without somatic comorbidities. This study examined the frequency of somatic comorbidities in SSD and their associations with psychosocial characteristics and disorder severity. METHODS: Cross-sectional data from the SOMA.SSD study were analyzed. SSD was diagnosed via Structured Clinical Interview for The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5). Somatic comorbidity was assessed with the physician-rated Cumulative Illness Rating Scale (CIRS). Patients with and without somatic comorbidity were compared on psychosocial and clinical variables. Ordinal logistic regression identified factors associated with SSD severity. RESULTS: A total of 241 SSD patients were included from a psychosomatic outpatient clinic (mean age 44.5 y, SD 13.7; 66.8% female). SSD severity was mild in 35.7%, moderate in 38.6%, and severe in 25.7%. Mean CIRS score was 4.4 (SD 3.18; range 0-52), with 61.0% of patients having at least one somatic comorbidity. Patients with somatic comorbidity were older and reported lower physical but higher mental health-related quality of life. Higher health anxiety was associated with greater SSD severity (β=0.287, P<.001), whereas somatic comorbidity was not linked to severity or psychosocial measures. CONCLUSION: Somatic comorbidities were common in SSD but did not influence severity or psychosocial profile, supporting the validity of the diagnosis independent of physical disease. Health anxiety emerged as a key correlate of severity, highlighting its relevance as treatment target.