The epidemiology of ICD‐11 bodily distress disorder and DSM‐5 somatic symptom disorder in new large‐scale population surveys within the World Mental Health Survey Initiative

Distressing somatic symptoms are common and disabling, but a lack of reliable classification of the underlying disorders has limited our understanding of the extent of their population burden. The new categories of bodily distress disorder (BDD) in the ICD-11 and somatic symptom disorder (SSD) in the DSM-5 were designed to address the fundamental weaknesses of previous conceptualizations, but have important differences in their criteria specifications. Three new large-scale population surveys within the World Mental Health (WMH) Survey Initiative, conducted in socially and culturally diverse settings, provide the opportunity to address questions regarding population prevalence, mental and physical health correlates, and associations with role impairment of BDD and SSD. WMH surveys were carried out in representative household samples of adults in Hong Kong, the Philippines, and Qatar (combined N=18,105 respondents). Multivariable regression analysis examined associations of BDD and SSD with socio-demographic variables, comorbid DSM-5 mental disorders, and chronic physical conditions. Role impairment was assessed by examining the mean number of health-related days out of role (DOR) in the 30 days before the interview, adjusting for socio-demographic variables and comorbidities. The point prevalence across the three settings was 2.0% for BDD, 3.5% for SSD, and 4.1% for either diagnosis. The point prevalence of BDD and especially of SSD was highest in Hong Kong, suggesting a role of cultural and social factors. Females were twice as likely as males to meet the criteria for either disorder. Prevalence increased with age. BDD and SSD were significantly associated with generalized anxiety, panic, post-traumatic stress, major depressive, and bipolar spectrum disorders, and associations were consistently stronger for BDD than SSD. More modest comorbidities were found with common chronic physical conditions (arthritis, asthma, diabetes mellitus, hypertension, and stomach or intestinal ulcer). BDD and SSD were both significantly associated with increased mean DOR after adjusting for comorbid mental disorders and chronic physical conditions, but the adjusted mean DOR was significantly higher in the BDD-only than in the SSD-only subsample (4.7 vs. 3.1, p<0.001). These findings attest to the high public health importance of BDD and SSD. Even though both are not highly prevalent in the community, their co-occurrence with common physical and mental disorders, and the fact that they are associated significantly with role impairment, provide strong reason for clinical attention.