Psychological risk factors of somatic symptom disorder: A systematic review and meta-analysis of cross-sectional and longitudinal studies

Objective: Current diagnostic concepts of somatic symptom disorder (SSD) in DSM-5 and bodily distress disorder (BDD) in ICD-11 require certain psychological criteria, but researchers have called for further specification. Therefore, in a first step, this systematic review and meta-analysis aimed to summarize the current evidence on psychological factors associated with SSD/BDD and/or disorder-relevant clinical outcomes such as symptom severity and impairment.

Methods: Psychological factors were systematically searched using Pubmed, Cochrane Library and Psycinfo via EBSCO. Studies providing original data in English or German, after 2009 were included. Cross-sectional, cohort and case-control studies investigating at least one psychological factor in individuals with SSD/BDD in the context of disorder-relevant outcomes were included.

Results: Forty-three eligible studies (n = 3760 patients) in SSD (none in BDD) provided data on at least one psychological factor, 37 in case-control format, 10 cross-sectional and 5 longitudinal. Meta-analyses of the case-control studies found patients with SSD to be more impaired by depression (SMD = 1.80), anxiety (SMD = 1.55), health anxiety (SMD = 1.31) and alexithymia (SMD = 1.39), compared to healthy controls. Longitudinal results are scarce, mixed, and require refining, individual studies suggest self-concept of bodily weakness, anxiety and depression to be predictive for persistent SSD and physical functioning.

Conclusion: This review provides a detailed overview of the current evidence of psychological factors in relation to SSD/BDD. Future studies on SSD and BDD should include under-studied psychological factors, such as negative affect, fear avoidance, or emotion regulation. More longitudinal studies are needed to assess the predictive value of these factors.