The MADRS scale measures the depression level of a participant. The total score was derived by adding the scores of the following 10 items: 1, apparent sadness; 2, reported sadness; 3, inner tension; 4, reduced sleep; 5, reduced appetite; 6, concentration difficulties; 7, lassitude; 8, inability to feel; 9, pessimistic thoughts; 10, suicidal thoughts. Each item was scored using a scale of 0 to 6 (a higher score indicates increased severity). The maximum total score is 60; 0, no depression; 60, severely depressed. Randomization value was defined as the assessment value done on Week 0. Change from Randomization in total score was the difference between MADRS total score at the time point being analyzed (Week 10) to Randomization.

The HAMD is a rating instrument for evaluating severity of symptoms of depression, was completed by the participant. The rating instrument used in this study was the 17-item version (HAM-D17). The Bech scale of the HAMD-17 is composed of 6 identified items out of the 17 items rated in HAMD-17 scale. Each item is rated on either a 3-point scale (0 to 2) or a 5-point scale (0 to 4). The following symptoms were rated on a 5-point scale (0-4): depressed mood, feeling of guilt, work and interests, psychomotor retardation, and anxiety (psychic). The following symptom was rated on a 3-point scale (0-2): somatic symptoms (general). Total score ranged from 0 to 22, with 0 indicating absence of symptoms and a higher score indicating greater severity of symptoms. Randomization value was defined as the assessment value done on Week 0. Change from Randomization in total score was the difference between Bech total score at the time point being analyzed (Week 10) to Randomization.

The IDS-CR is a standardized 30-item, clinician rated scale to assess the severity of a participant's depressive symptoms. The items were rated on a 4-point scale of 0-3, where 0 indicated absence of symptom and higher score indicated greater severity of symptom. In order to calculate the total score of IDS-CR, the following procedures were used: either item 11 or 12 were scored; either item 13 or 14 were scored; if both items 11 and 12 (or 13 and 14) were scored, the highest of the items was scored. The total score was obtained by adding the scores of 28 items of the 30 items. Total scores range from 0-84, with a score of 0 indicating no depression and a score of 84 indicating the most severe depression. Randomization value was defined as the assessment value done on Week 0. Change from Randomization in total score was the difference between IDS-CR total score at the time point being analyzed (Week 10) to Randomization.