Patient description: The patient is a 47-year-old Asian woman complaining of persistent feelings of sadness. She lost interest in activities she used to enjoy. She states that her mood is mostly depressed for the past 3 weeks. She also lost her appetite , which led to about 5kg weight loss. She complains of loss of energy and feelings of worthlessness nearly every day. She is not using any drugs and she does not smoke. She doesn't drink alcohol. She used to exercise every day for at least 30 min. But she doesn't have enough energy to do so for the past 3 weeks. She also has some digestive issues recently. She is married and has 4 children. She is menopausal. Her husband was recently diagnosed with colon cancer and he is starting his chemotherapy. There is nothing remarkable in her past medical history and her drug history is only positive for Vit D3 1000 units daily. Her family history is negative for any psychologic problems. Her HAM-D score is 20.

Clinical trial eligibility criteria: eligible ages (years): 18.0-64.0,  Depressive Disorder, Major Body mass index (BMI) must be between 18 and 32 kilogram per square meter (kg/m^2) inclusive Related to symptoms of depression: Participant must meet the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV or V diagnostic for Major Depressive Disorder [MDD] (International Classification of Diseases (ICD)-code F32.x and F33.x), without psychotic features, as confirmed by the MINI 6.0; participant must have an IDS-C30 total score greater than or equal to (>=) 30 using the semi-structured interview guide for the IDS-C30 Participant is, during this episode of depression, treatment naïve OR treated with at most one Selective serotonin reuptake inhibitor (SSRI) over a minimum of 6 weeks and a maximum of 6 months, and subject is being treated at an adequate dose, showing a partial response at enrolment A woman of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test upon admission A woman must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during the study and for at least 3 months after receiving the last dose of study drug  Has a primary DSM-IV or V diagnosis of general anxiety disorder (GAD), panic disorder, obsessive compulsive disorder, posttraumatic stress disorder, anorexia nervosa, or bulimia nervosa. Participants with comorbid GAD, social anxiety disorder, or panic disorder for whom MDD is considered the primary diagnosis are not excluded Has a length of current major depressive episode greater than (>) 24 months despite adequate treatment Has failed more than 2 treatments with a different pharmacological mode of action despite an adequate dose and duration during a previous, or the current depressive episode Participant has a history of substance use disorder according to DSM-V except nicotine or caffeine, within 6 months before Screening. However, participants who have completed a treatment for (alcohol) addiction more than 8 weeks prior to first dose administration and are under continuous control of the study center, may be included if the risk to fall back is considered minimal and no significant abnormalities are shown in clinical laboratory or other predose safety assessments Obstructive sleep apnea/hypopnea (apnea/hypopnea index >10) or restless legs syndrome (periodic leg movements with arousal index >15) as assessed on the first or second polysomnography (PSG) recording during screening