Current somatoform disorders in Norway: prevalence, risk factors and comorbidity with anxiety, depression and musculoskeletal disorders

Background The future existence of somatoform disorders (SDs) has recently been debated. The objectives of this study were to investigate the prevalence of current SDs (defined as the presence of multisomatoform disorder [MSD] or somatoform disorders not otherwise specified [SDnos], without psychosocial impairment) and severe current SDs (MSD or SDnos with psychosocial impairment) in Norway. Differences in markers of severe current SDs, anxiety/depression and self-reported musculoskeletal disorders were explored. In addition, psychological distress and utilization of healthcare in subclasses (defined according to comorbidity with anxiety, depression and musculoskeletal disorders) of severe current SDs were examined. Methods We interviewed 1,247 respondents using the Composite International Diagnostic Interview (CIDI) in the Oslo–Lofoten general population survey in 2000–2001. Six-month prevalence rates (%) and 95% confidence intervals (CIs) for current SDs were investigated by gender and age. Risk factors of disorders, psychological distress, healthcare utilization and use of medication were explored using logistic regression analyses. Results The overall prevalence rate for severe current SDs was 10.2%. When psychosocial impairment was excluded as a criterion, the rate increased to 24.6%. Anxiety was strongly correlated with severe current SDs. Comorbidity of severe current SDs with anxiety/ depression was 45%, and with musculoskeletal disorders, 43%. Analysis of healthcare utilization and use of medication showed that the presence of a comorbid psychiatric condition was more important than the presence of somatoform disorders alone. Conclusion Somatoform symptoms alone (with no psychiatric comorbidity) should not be considered a psychiatric disorder.