To the best of our knowledge, this is the first population-based study evaluating the relationship between the Val158Met polymorphism and anxiety and depression measured by the Hospital Anxiety and Depression Scale (HADS). The dimensional structure of HADS has been found stable across age-groups [9], and the HADS questionnaire is widely used to measure anxiety and depression in somatic and psychiatric patients as well as in the general population [10]. Previous studies on HADS have shown good reliability and validity compared to other symptom scales of depression and anxiety [10-15].
