Screening for DSM-5 Somatic Symptom Disorder: Diagnostic Accuracy of Self-Report Measures Within a Population Sample

Objective: The new DSM-5 somatic symptom disorder was introduced to improve the diagnosis of persons experiencing what used to be called somatoform disorders. So far, it is unclear whether existing self-report measures are useful to detect the new somatic symptom disorder. This study investigates the diagnostic accuracy of three self-report questionnaires that measure somatic complaints (15 item Patient Health Questionnaire [PHQ-15]) and psychological features (7-item Whiteley Index [WI-7]; Scale for Assessing Illness Behavior [SAIB]), in detecting somatic symptom disorder.

Methods: A nationally representative general population survey was performed resulting in 250 participants (minimum age = 14 years. 12.8% participation rate). Assessment took place at baseline and 12-month follow-up. Individual and combined diagnostic accuracy of the PHQ-15, WI-7, and SAIB in detecting somatic symptom disorder was evaluated using the area under the curve (AUC) of a receiver operating characteristic.

Results: Diagnostic accuracy was adequate to good for each individual questionnaire (PHQ-15: AUC = 0.79, p < .001, 95% confidence interval [CI] = 0.73-0.85; WI-7: AUC = 0.76, p < .001, 95% CI = 0.69-0.83; SAIB: AUC = 0.77, p < .001, 95% CI = 0.71-0.83). Combining the PHQ-15 and the WI-7 slightly improved diagnostic accuracy (AUC = 0.82, p < .001, 95% CI = 0.77-0.88), as did the combination of all three questionnaires (AUC = 0.85, p < .001, 95% CI = 0.79-0.90).

Conclusions: The PHQ-15, WI-7, and SAIB are useful screening instruments to detect persons at risk for somatic symptom disorder, and a combination of these three instruments slightly improves diagnostic accuracy. Their use in routine care will lead to improved detection rates.