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

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. 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. 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. 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.