The association between anxiety, depression, and somatic symptoms in a large population: The HUNT-II study

Objective: Somatic symptoms are prevalent in the community, but at least one third of the symptoms lack organic explanation. Patients with such symptoms have a tendency to overuse the health care system with frequent consultations and have a high degree of disability and sickness compensation. Studies from clinical samples have shown that anxiety and depression are prevalent in such functional conditions. The aim of this study is to examine the connection between anxiety, depression, and functional somatic symptoms in a large community sample. Method: The HUNT-II study invited all inhabitants aged 20 years and above in Nord-Trondelag County of Norway to have their health examined and sent a questionnaire asking about physical symptoms, demographic factors, lifestyle, and somatic diseases. Anxiety and depression were recorded by the Hospital Anxiety and Depression Scale. Of those invited, 62,651 participants (71.3%) filled in the questionnaire. A total of 10,492 people were excluded due to organic diseases, and 50,377 were taken into the analyses. Results: Women reported more somatic symptoms than men (mean number of symptoms women/men: 3.8/2.9). There was a strong association between anxiety, depression, and functional somatic symptoms. The association was equally strong for anxiety and depression, and a somewhat stronger association was observed for comorbid anxiety and depression. The association of anxiety, depression, and functional somatic symptoms was equally strong in men and women (mean number of somatic symptoms men/women in anxiety: 4.5/5.9, in depression: 4.6/5.9, in comorbid anxiety and depression: 6.1/7.6, and in no anxiety or depression: 2.6/3.6) and in all age groups. The association between number of somatic symptoms and the total score on Hospital Anxiety and Depression Scale was linear. Conclusion: There was a statistically significant relationship between anxiety, depression, and functional somatic symptoms, independent of age and gender.