HADS is a self-assessment scale containing 14 questions developed to detect states of anxiety and depression, specifically designed for non-psychiatric hospital departments [20]. To each question there are four possible response options which are scored from 0 to 3 points depending on the severity of the symptoms. There are seven questions related to depressive symptoms (HADS-D subscale) and seven questions concerning anxiety symptoms (HADS-A subscale). Based on empirical knowledge a clinically significant anxiety disorder is defined by a HADS-A score of ≥ 8, while depressive disorder is defined by HADS-D ≥ 8. These limits are found to give the optimal balance between sensitivity and specificity [11]. Based on HADS-A and HADS-D scores, the participants were classified into one of five groups: 1) No disorder (controls): both HADS-A <8 and HADS-D <8; 2) Anxiety disorder: HADS-A ≥ 8; 3) Depressive disorder: HADS-D ≥ 8; 4) Combined disorder: both HADS-A ≥ 8 and HADS-D ≥ 8; and 5) Unclassified. This last group consisted of subjects with insufficient HADS score data. Some had total HADS scores but unavailable subscale scores, while others only
