Treatment patterns of TRD participants will be assessed over time.

Treatment duration is defined as the time interval between baseline and time to next therapy (since the date of the first and second regimen to the start of third regimen).

Treatment patterns for TRD participants will be determined by distribution of every line of the treatment regimen including pharmaceutical and non-pharmaceutical treatments.

Sequence of drugs taken by TRD participants will be determined.

The MADRS is a 10 item scale for the evaluation of depressive symptoms (Montgomery et al 1979). The MADRS evaluates apparent sadness, reported sadness, inner tension, sleep, appetite, concentration, lassitude, interest level, pessimistic thoughts, and suicidal thoughts. Each MADRS item is rated on a 0 to 6 scale with a total score ranging from 0 60. Higher MADRS scores indicate higher levels of depressive symptoms (more severe condition) and lower scores indicate a decreased severity of depression.

SDS is a composite of 3 self-rated items designed to measure the extent to which 3 major sectors in the participant's life are impaired by panic, anxiety, phobic, or depressive symptoms. The participant rates the extent to which his or her (1) work, (2) social life or leisure activities, and (3) home life or family responsibilities are impaired by his or her symptoms on a 10-point visual analog scale. To get a total score add up the 3 individual scores and the total score ranges from "0 = unimpaired" to "30 = highly impaired". Higher scores indicate worsening.

Suicidal ideation or behavior will be measured using C SSRS score. C-SSRS is a clinician rated assessment of suicidal behavior and/ or intent. Scale consists of 28 items in 4 sections: suicide behavior, actual attempts, suicidal ideation, and intensity of ideation. Suicidal ideation consists of 5 yes/no items: wish to be dead, non-specific active suicidal thoughts, active suicidal ideation with any methods (not plan) without intention to act, active suicidal ideation with some intent to act without specific plan, active suicidal ideation with specific plan and intent. Worsening of suicidal ideation was an increase in severity of suicidal ideation from baseline.

Total healthcare costs and healthcare costs related to depression will be determined in TRD participants.

Work productivity loss was measured by Work Productivity and Activity Impairment Questionnaire (WPAI). The WPAI is a validated, self-administered questionnaire that assesses work and activity impairment during the past 7 days. The WPAI produces 4 types of scores: absenteeism (work time missed), presenteeism (impairment at work/reduced on the job effectiveness), work productivity loss (overall work impairment/absenteeism plus presenteeism), and activity impairment. The WPAI outcomes are expressed as impairment percentages, with higher numbers indicating greater impairment and less productivity, that is, worse outcomes.

Indirect cost associated with daily functioning loss will be determined.

Indirect cost associated with caregiver burden will be determined.

Quality of life will be measured by EuroQol-5 Dimension (EQ-5D). The EQ-5D descriptive system comprises the following 5 dimensions: Mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each of the 5 dimensions is divided into 3 levels of perceived problems (Level 1 indicating no problem, Level 2 indicating slight problems, Level 3 indicating extreme problems). The participant selects an answer for each of the 5 dimensions considering the response that best matches his or her health "today." The descriptive system can be represented as a health state. The EQ-VAS self-rating records the respondent's own assessment of his or her overall health status, on a scale of 0 (worst imaginable health state) to 100 (best imaginable health state).