Clinical value of DSM IV and DSM 5 criteria for diagnosing the most prevalent somatoform disorders in patients with medically unexplained physical symptoms (MUPS).

Objective: This study aimed (1) to describe frequencies of DSM IV somatisation disorder, undifferentiated somatoform disorder and pain disorder versus DSM 5 somatic symptom disorder (SSD) in a multi-setting population of patients with medically unexplained physical symptoms (MUPS), (2) to investigate differences in sociodemographic and (psycho)pathological characteristics between these diagnostic groups and (3) to explore the clinical relevance of the distinction between mild and moderate DSM 5 SSD.

Methods: We used baseline data of a cohort of 325 MUPS patients. Measurements included questionnaires about symptom severity, physical functioning, anxiety, depression, health anxiety and illness perceptions. These questionnaires were used as proxy measures for operationalization of DSM IV and DSM 5 diagnostic criteria.

Results: 92.9% of participants fulfilled criteria of a DSM IV somatoform disorder, while 45.5% fulfilled criteria of DSM 5 SSD. Participants fulfilling criteria of DSM 5 SSD suffered from more severe symptoms than those only fulfilling criteria of a DSM IV somatoform disorder(mean PHQ-15 score of 13.98 (SD 5.17) versus 11.23 (SD 4.71), P-value<0.001). Furthermore their level of physical functioning was significantly lower. Compared to patients with mild SSD, patients with moderate SSD suffered from significantly lower physical functioning and higher levels of depression.

Conclusion: Within a population of MUPS patients DSM 5 SSD criteria are more restrictive than DSM IV criteria for somatoform disorders. They are associated with higher symptom severity and lower physical functioning. However, further specification of the positive psychological criteria of DSM 5 SSD may improve utility in research and practice.