Somatisation as a risk factor for incident depression and anxiety.

OBJECTIVE: In this study, we aimed to examine somatisation as a risk factor for the onset of depressive and anxiety disorders.

METHODS: 4-year follow-up data from the Netherlands Study of Depression and Anxiety (NESDA), a multisite cohort study of the course of depression and anxiety, was analysed. Participants (18-65 years) without a lifetime depressive or anxiety disorder at baseline were included (n=611). Somatisation was measured at baseline with the somatisation subscale of the 4 Dimensional Symptoms Questionnaire. Onset of depression and anxiety was assessed with the CIDI interview at 2-year and 4-year follow-up.

RESULTS: Somatisation was a risk factor for the incidence of depression [Hazard Ratio per unit increase (HR); 95% Confidence Interval (CI): 1.13; 1.09-1.17] and anxiety [HR; 95% CI: 1.14; 1.09-1.18]. Associations attenuated but remained statistically significant after adjusting for socio-demographic characteristics, chronic somatic disorders, and baseline levels of (subclinical) depressive or anxiety symptoms [adjusted HR for depression; 95% CI: 1.06; 1.00-1.12, adjusted HR for anxiety; 95% CI: 1.13; 1.07-1.20].

CONCLUSION: Persons who somatise have an increased risk of becoming depressed or anxious in subsequent years, over and above baseline levels of depressive or anxiety symptoms. They may represent a target group for prevention of depressive and anxiety disorders.