Pain in somatoform disorders: is somatoform pain disorder a valid diagnosis?

Objective: Investigate the validity of DSM-IIIR somatoform pain disorder (SPD) by comparing subgroups of somatoform disorder patients on several measures of psychopathology. Method: A total of 144 patients with unexplained physical symptoms were referred from non-psychiatric departments. Among these, 127 patients with somatoform disorders were identified, classified according to the Structured Clinical Interview for DSM (SCID) diagnostic interview, and rated with scales for somatization, anxiety, depression and personality traits. Results: Patients presenting pain did not differ significantly from patients presenting non-pain symptoms on measures of symptoms and personality traits. Correspondingly, patients with SPD did not differ significantly from patients with conversion disorder (CD), while patients with Somatization disorder (SD) had higher scores on most scales for psychopathology and personality disorder. Conclusion: Significant diagnostic and symptomatic overlap was found between SPD and CD, and although the statistical power of the study was modest, the study questions the validity of the current definition of SPD.