Epidemiology of the Association Between Somatoform Disorders and Anxiety and Depressive Disorders: An Update

Objective: To review the available epidemiological evidence on associations between somatoform disorders with anxiety and depressive disorders. Results: Clinical and population-based studies have found that the co-occurrence of some types of somatoform disorders (e.g., somatization disorder, somatic-symptom-index (SSI)4,6, and pain disorder) and anxiety and depressive disorders is common. These findings may suggest either a causal relationship between these disorders or that they share some common etiological factors. For other forms of somatoform disorders, empirical evidence about co-occurrence is even thinner or not available at all, especially from non-western settings. Conclusion: Some implications of how these findings, or the absence of them, can help us understand better the etiology of somatoform disorders and improve the classification of mental disorders as a whole are discussed. DSM = Diagnostic and Statistical Manual of Mental Disorders; DIS = Diagnostic Interview Schedule; ECA = Epidemiological Catchment Area Program; FGD = functional gastrointestinal disorders; GAD = general anxiety disorder; OR = odds ratio; PTSD = posttraumatic stress disorder; SSI = Somatic Symptom Index.