MADRS is a clinician-administered scale designed to measure depression severity and detects changes due to antidepressant treatment. The MADRS evaluates the following 10 items: apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, concentration difficulties, lassitude, inability to feel, pessimistic thoughts, and suicidal thoughts. Each item is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score range of 0-60 which is calculated by adding the scores of all 10 items. Higher scores represent a more severe condition.

Full analysis set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

An adverse event (AE) was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Treatment-emergent were events between the initial administration of study drug and 2 days after the last administration of study drug.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug.

Percentage of participants with clinically significant laboratory abnormalities were reported which included Gamma-glutamyl transferase (GGT), Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Alkaline Phosphatase (ALP), Creatine Kinase (CK), Lactate Dehydrogenase (LDH), Albumin , bicarbonate, bilirubin, calcium, chloride, cholesterol, creatinine, direct bilirubin, glucose, high density lipoprotein (HDL) cholesterol, hemoglobin A1C, low density lipoprotein (LDL) cholesterol, phosphate, potassium, protein, sodium, triglycerides, urate, and urea nitrogen.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure; n (number analyzed) signifies those participants who were evaluable for specified categories.

Change from baseline in vital signs (SBP and DBP) at Day 8 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital signs (SBP and DBP) at Day 22 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital signs (SBP and DBP) at Day 42 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital signs (SBP and DBP) at endpoint was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure. Endpoint (double-blind [DB]) values are from the last measurement within the double-blind period.

Change from baseline in vital sign (PR) at Day 8 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital sign (PR) at Day 22 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital sign (PR) at Day 42 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital sign (PR) at endpoint (Week 6) was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

Change from baseline in vital Sign (temperature) at Day 8 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital Sign (temperature) at Day 22 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital Sign (temperature) at Day 42 was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

Change from baseline in vital Sign (temperature) at endpoint (Week 6) was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

Change from baseline in physical examination (waist circumference) was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

Change from baseline in physical examination (body weight) was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

Change from baseline in physical examination (BMI) was reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

Percentage of participants with treatment-emergent abnormal ECG values (Heart rate less than or equal to [<=] 50 or greater than or equal to [>=] 100 beats per minute [bpm], PR interval <=120 or >=200 milliseconds [msec], QRS interval <=60 or >=120 msec, and QT interval <=200 or >=500 msec) outside pre-defined limits were reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure; n (number analyzed) signifies those participants who were evaluable for specified categories.

C-SSRS is a clinician-rated instrument that reports severity of both suicidal ideation and behavior. Suicidal ideation was classified on a 5-item scale: 1 (wish to be dead), 2 (nonspecific active suicidal thoughts), 3 (active suicidal ideation with any methods [not plan] without intent to act), 4 (active suicidal ideation with some intent to act, without specific plan), and 5 (active suicidal ideation with specific plan and intent). Suicidal behavior is classified on a 5-item scale: 0 (no suicidal behavior), 1 (preparatory acts or behavior), 2 (aborted attempt), 3 (interrupted attempt), and 4 (actual attempt). More than 1 classification can be selected provided they represent separate episodes. Minimum total score 0, maximum total score 5; higher total scores indicate more suicidal ideation and/or suicidal behavior. If no events qualify for score of 1 to 10, score of 0 was assigned (0= "no event that can be assessed on the basis of C-SSRS"). Higher scores indicate greater severity.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

Effect on sexual functioning was assessed using the ASEX score. The ASEX is a five-item rating scale that quantifies sex drive, arousal, vaginal lubrication/penile erection, ability to reach orgasm, and satisfaction from orgasm. Each of the 5 items is rated on a 6-point scale, ranging from 1 to 6. The 5 items are summed to create a total score, ranging from 5 to 30, with the higher scores indicating more sexual dysfunction.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

Intensity of discontinuation symptoms was assessed (for example: underlying depression; anxiety-nervousness; dysphoric mood/depression; difficulty concentrating; weakness; fatigue-lethargy-lack of energy; irritability), using the Physician Withdrawal Checklist (PWC-20) administered by a trained clinician/rater. Symptoms are rated on a scale 0 (No symptom present) and 3 (severe symptoms). Total scores range from 0 to 24 calculated by adding the scores of following 8 items: Nausea-Vomiting, Diarrhea, Poor Coordination, Diaphoresis, Tremor-Tremulousness, Dizziness-Lightheadedness, Increased Acuity Sound Smell Touch, Paresthesias. Higher scores indicating more severe symptoms.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.

MADRS is a clinician-administered scale designed to measure depression severity and detects changes due to antidepressant treatment. The MADRS evaluates the following 10 items: apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, concentration difficulties, lassitude, inability to feel, pessimistic thoughts, and suicidal thoughts. Each item is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score range of 0-60 which is calculated by adding the scores of all 10 items. Higher scores represent a more severe condition. The ISI has 7 questions, each rated on a 5-point Likert scale ranging from 0 to 4. The total score is calculated as the sum of the 7 items ranging from 0 to 28. Higher scores represent a more severe condition.

Full analysis set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure; 'n' (number analyzed) signifies those participants who were evaluable for specific category.

The ISI is a commonly used, 7-item psychometrically validated measure used to rate insomnia. Each item is scored 0 (no problem) to 4 (very big problem) with total between 0-28 which is calculated by adding the scores of all 7 items (absence of insomnia [0-7]; sub-threshold insomnia [8-14]; moderate insomnia [15-21]; and severe insomnia [22-28]). The change in ISI total score from baseline at DB endpoint was evaluated. Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here 'N' (number of participants analyzed) signifies the evaluable participants for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

Responders are defined as participants with a >=50 percent (%) improvement in the MADRS total score from baseline to a given timepoint. MADRS is a clinician-administered scale designed to measure depression severity and detects changes due to antidepressant treatment. The MADRS evaluates the following 10 items: apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, concentration difficulties, lassitude, inability to feel, pessimistic thoughts, and suicidal thoughts. Each item is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score range of 0-60 which is calculated by adding the scores of all 10 items. Higher scores represent a more severe condition. Participants with missing values at a given time point were imputed as non-responders.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug.

Participants with a MADRS total score of less than or equal to (<=) 8, <=10, and <=12 at a given time point were considered as remitters. MADRS is a clinician-administered scale designed to measure depression severity and detects changes due to antidepressant treatment. The MADRS evaluates the following 10 items: apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, concentration difficulties, lassitude, inability to feel, pessimistic thoughts, and suicidal thoughts. Each item is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score range of 0-60 which is calculated by adding the scores of all 10 items. Higher scores represent a more severe condition. Participants with missing values at a given time point were imputed as non-responders.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug.

HAM-A is a 14-item scale designed to measure anxiety in individuals. Each question reflects a symptom of anxiety and physical as well as mental symptoms are represented. Each of the 14-items in the scale is scored on a 5-point scale, ranging from 0 (a complete lack of that symptom) to 4 (a very severe show of anxiety with that symptom). The total score ranges from 0 to 56 which is calculated by adding the scores of all 14 items, where 0-13 indicates normal range, 14-17 indicates mild severity, 18 -24: mild to moderate severity, 25 -30: moderate to severe, and >=31: severe. Higher score indicates worsening. Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here 'N' (number of participants analyzed) signifies the evaluable participants for this outcome measure.

Participants with a >=50 percent improvement in the HAM-A total score from baseline at a given timepoint were considered as responders. HAM-A is a 14-item scale designed to measure anxiety in individuals. Each question reflects a symptom of anxiety and physical as well as mental symptoms are represented. Each of the 14-items in the scale is scored on a 5-point scale, ranging from 0 (a complete lack of that symptom) to 4 (a very severe show of anxiety with that symptom). The total score ranges from 0 to 56 which is calculated by adding the scores of all 14 items, where 0-13 indicates normal range, 14-17 indicates mild severity, 18 -24: mild to moderate severity, 25 -30: moderate to severe, and >=31: severe. Higher score indicates worsening. Participants with missing values at a given time point were imputed as non-responders.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug.

The CGI-S provides an overall clinician-determined summary measure of the severity of the participant's illness that takes into account all available information, including knowledge of the participant's history, psychosocial circumstances, symptoms, behavior, and the impact of the symptoms on the participant's ability to function. The CGI-S is a 7-point global assessment scale that measures the clinician's impression of the severity of illness exhibited by a participant, rating according to: 1=normal (not at all ill); 2=borderline ill; 3=mildly ill; 4=moderately ill; 5=markedly ill; 6=severely ill; and 7=among the most extremely ill participants. Higher scores indicate worsening. Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (number of participants analyzed) signifies participants evaluable for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

The SDS is a 5-item questionnaire which has been widely used and accepted for assessment of functional impairment and associated disability. The first 3 items assess disruption of (1) work/school, (2) social life, and (3) family life/home responsibilities using a 0-10 rating scale. The scores for the first 3 items are summed to create a total score of 0-30, where a higher score indicates greater impairment. It also has 1 item on days lost from school or work and 1 item on days when underproductive. Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

MADRS is a clinician-administered scale designed to measure depression severity and detects changes due to antidepressant treatment. The MADRS evaluates the following 10 items: apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, concentration difficulties, lassitude, inability to feel, pessimistic thoughts, and suicidal thoughts. Each item is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total possible score range of 0-60 which is calculated by adding the scores of all 10 items. Higher scores represent a more severe condition. Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure; 'n' (number analyzed) signifies those participants who were evaluable for specific category.

Exposure on the hypothalamic-pituitary-adrenal (HPA) axis in participants with MDD was evaluated by assessing change in salivary cortisol levels.

Biomarker analysis set included all randomized participants who received at least 1 dose of study drug during the double-blind phase and had biomarker data at baseline. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure; 'n' (number analyzed) signifies those participants who were evaluable for specific timepoints.

Plasma concentrations of Seltorexant and its metabolites (M12 and M16) over time were reported.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure; 'n' (number analyzed) signifies those participants who were evaluable for specific timepoints.

The PHQ-9 is a 9-item, Patient Reported Outcome (PRO) measure to assess depressive symptoms. The scale scores each of the 9 symptom domains of the Diagnostic and Statistical Manual of Mental Disorders-5th Edition (DSM-5) major depressive disorder (MDD) criteria. Each item is rated on a 4 point scale (0=not at all, 1=several days, 2=more than half the days, and 3=nearly every day). The participants item responses are summed to provide a total score (range of 0 to 27), with higher scores indicating greater severity of depressive symptoms. The severity of the PHQ-9 is categorized as follows: None-minimal (0-4), Mild (5-9), Moderate (10-14), Moderately Severe (15-19) and Severe (20-27).

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

The SHAPS is a 14-item, self-report instrument to assess hedonic capacity in adults with MDD. Each of the items has a set of 4 response categories-Definitely Agree (=1), Agree (=2), Disagree (=3), and Definitely Disagree (=4). A total score is created with either of the Disagree responses receiving a score of 1 and either of the Agree responses receiving a score of 0. The participants item responses are summed to provide a total score ranging from 0 to 14. A higher total SHAPS score indicates higher levels of current anhedonia.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

The PROMIS-SD Short Form subscale consists of a static 8 item questionnaire. It assesses the concepts of sleep initiation (2 items), quality of sleep (3 items), early morning feelings (2 items) and worrying about sleep (1 item). Responses to each of the 8 items range from 1 to 5, and the range of possible summed raw scores is 8 to 40. Higher scores on the PROMIS-SD indicate more of the concept measured (disturbed sleep). Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure.

The PROMIS-Fatigue Short Form subscale consists of a static 8 item questionnaire. It assesses a range of symptoms from mild subjective feelings of tiredness to an overwhelming, debilitating, and sustained sense of exhaustion that likely decreases one's ability to execute daily activities and function normally in family or social roles. Ratings are done on a 5-item Likert scale ranging from 0 (not at all) to 5 (very much) or 0 (never) to 5(always) depending upon the question answered. Higher scores on the PROMIS-F indicate more of the concept measured (fatigue). Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

The PGI-S is a self-report scale to measure severity of illness (1=none, 2=mild, 3=moderate, 4=severe). Higher score indicates more illness severity. Negative change in score indicates improvement.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies those participants who were evaluable for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

EQ-5D-5L descriptive system comprises of 5 dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels of perceived problems (1-no problem, 2-slight problems, 3-moderate problems, 4-severe problems, 5-extreme problems). The responses to 5 EQ-5D-5L dimensions were scored using a utility-weighted algorithm to derive an EQ-5D-5L health status index score between 0 (death) to 100 (full health).

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (number of participants analyzed) signifies participants who were evaluable for this outcome measure. Endpoint (DB) values are from the last measurement within the double-blind period.

The EQ-5D-5L is a standardized instrument for use as a measure of health outcome, primarily designed for self-completion by respondents. It consists of the EQ-5D-5L descriptive system and the EQ visual analogue scale (EQ-VAS). EQ-5D-5L (describing and valuing health-related quality of life) descriptive system comprises 5 dimensions of health (mobility, self -care, usual activities, pain/discomfort, and anxiety/depression) to describe the participant's current health state. Each dimension comprises 5 levels with corresponding numeric scores, where 1 indicates no problems, and 5 indicates extreme problems. Higher scores representing a better health state. An increase in the EQ-5D-5L total score indicates improvement. EQ-VAS self-rating records respondent's own assessment of his/her overall health status at time of completion, on scale of 0 (worst health you can imagine) to 100 (best health you can imagine).

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (number of participants analyzed) signifies participants who were evaluable for this outcome measure. Endpoint (DB) values: last measurement within double-blind period.

The WLQ is to assess the on-the-job impact of chronic health problems and/or treatment ("work limitations") in adults. It is a 8-item questionnaire self-report rating scale developed to measure the on-the-job impact of chronic health problems and/or treatment ("work limitations"). It comprises five dimensions of limitations: handling time, physical, mental-interpersonal, productivity loss and output demands. Participants respond to each item with options ranging from 'Almost all of the time' to 'none of the time', or 'Does not apply to my job'. Each dimension of limitations have a scale score ranging from 0 to 100 with lower score indicating low level of work limitations.

Full analysis set included participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, 'N' (number of participants analyzed) signifies participants who were evaluable for this outcome measure; 'n' (number analyzed) signifies those participants who were evaluable for specific categories. Endpoint (DB) values are from the last measurement within the double-blind period.

Intensity of discontinuation symptoms was assessed (for example: underlying depression; anxiety-nervousness; dysphoric mood/depression; difficulty concentrating; weakness; fatigue-lethargy-lack of energy; irritability), using the Physician Withdrawal Checklist (PWC-20) administered by a trained clinician/rater. Symptoms are rated on a scale 0 (No symptom present) and 3 (severe symptoms). Total scores range from 0 to 24 calculated by adding the scores of following 8 items: Nausea-Vomiting, Diarrhea, Poor Coordination, Diaphoresis, Tremor-Tremulousness, Dizziness-Lightheadedness, Increased Acuity Sound Smell Touch, Paresthesias. Higher scores indicating more severe symptoms.

Safety analyses set included all participants who were randomly assigned to study drug and received at least 1 dose of study drug. Here, N (numbers of participants analyzed) signifies numbers of participants evaluable for this outcome measure.