Is severity a clinically meaningful specifier of somatic symptom disorder?

Few existing studies have investigated the clinical relevance of Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) somatic symptom disorder (SSD) severity rated by clinicians. We examined the association of SSD severity with psychiatric and medical comorbidity, psychological features and help-seeking attitude and behaviours.

A total of 123 patients with SSD were prospectively recruited and completed several types of self-report instrument. Information about medical comorbidity and healthcare use was gathered from the participants and medical record review. Common comorbid psychiatric diagnoses of SSD were assessed by psychiatrists. Group differences of patients with SSD of varying severity were assessed with ANOVA and chi-square tests. Multiple linear regression models were used to examine the relationships between SSD severity and psychological features.

Prevalence of medical comorbidity and comorbid psychiatric diagnoses of SSD was not significantly different among patients with varying SSD severity. Patients with severe SSD had the highest Patient Health Questionnaire-15 (PHQ-15), Health Anxiety Questionnaire (HAQ), Beck Depression Inventory-II (BDI-II) and Beck Anxiety Inventory (BAI) scores. Help-seeking behaviour was not associated with SSD severity. After controlling for demographic variables, the associations between 'severe SSD' and the PHQ-15, HAQ, BDI-II and BAI scores were significant.

SSD severity rated by clinicians was not associated with comorbid medical or psychiatric diagnoses. Compared to patients with mild/moderate SSD, patients with severe SSD not only had higher somatic distress and health anxiety but also higher levels of anxiety/depression. However, SSD severity was not associated with help-seeking attitude and behaviour.