Abstract
<title>Abstract</title> <p> <italic> <bold>Background</bold> </italic> : Somatic symptom disorder (SSD), as defined in DSM-5, emphasizes psychobehavioral responses to somatic symptoms and specifies three severity levels (mild, moderate, severe). However, the clinical relevance of these levels remains insufficiently established, particularly in medical inpatients. We examined whether a DSM-5–aligned self-report-based operationalization of these severity levels corresponds to clinically meaningful differences in health status. <italic> <bold>Methods</bold> </italic> : Cross-sectional analysis of baseline observational data from SomPsyNet, an intervention addressing psychosocial distress at three somatic hospitals in Basel, Switzerland (06/2020–12/2022). SSD was evaluated with the Somatic Symptom Scale-8 (SSS-8), Somatic Symptom Disorder-B Criteria Scale (SSD-12), and persistence indicators. Severity levels were derived from the number of SSD-12 subdimensions scoring≥10. Health status was assessed through SF-36 Mental/Physical Component Summary scores (MCS, PCS). Group differences and receiver operating characteristics were analyzed. <italic> <bold>Results</bold> </italic> : The sample comprised 2,951 inpatients. Overall, 20.5% met criteria for any SSD severity level (95%CI: 19.1–22.0%): 9.0% mild (95%CI: 8.0–10.1%), 1.0% moderate (95%CI: 0.7–1.4%), 10.5% severe (95%CI: 9.5–11.7%). SSD-positive participants had lower MCS/PCS than SSD-negative participants (each <italic>p</italic> <.001). Severe cases had lower MCS than mild cases (9.8-point difference, <italic>p</italic> <.001), whereas PCS did not differ. The predefined SSD-12 subdimension cut-off≥10 showed better discrimination of impaired mental health than the stricter cut-off≥12 (AUC 0.70 vs. 0.65; <italic>p</italic> <.001). <italic> <bold>Conclusions</bold> </italic> : Our DSM-5–aligned SSD severity classification yielded few moderate cases and clearer differentiation between mild and severe groups. Severity differences were reflected in mental rather than physical health status. These findings support clinical relevance of symptom-related distress in medical inpatients. <bold>Registry:</bold> ClinicalTrials.gov, TRN: NCT04269005, Registration date: 13 February 2020. </p>