Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Randomized, Double-blind, Multicenter, Active-controlled Study to Evaluate the Efficacy, Safety, and Tolerability of Fixed Doses of Intranasal Esketamine Plus an Oral Antidepressant in Adult Subjects With Treatment-resistant Depression
Brief Summary: The purpose of this study is to compare the efficacy and safety of switching treatment-resistant depression (TRD) participants from a prior antidepressant treatment (to which they have not responded) to either intranasal esketamine plus a new oral antidepressant or switching to a new oral antidepressant plus intranasal placebo.


Options:
A: Inclusion Criteria:

* Satisfy DSM-IV-TR criteria for Major Depressive Episode
* 18 years or over
* Does not have a diagnosis of schizophrenia, schizoaffective disorder, rapid cycling bipolar disorder, or current psychotic symptoms
* No known sensitivity to ketamine
* No ECT in the last 3 months
* No drug or alcohol abuse in the last 12 months
* Able to give informed consent
* Score at least 24 on Mini Mental State Examination
B: Inclusion Criteria:

* Aged 18-55 years
* Fulfilled the DSM-IV criteria of major depressive disorder
* Had a 17-item Hamilton Rating Scale for Depression (HAMD-17)\>or= 18
* No DSM-IV diagnosis of substance abuse or dependence (including alcohol) within the past 6 months
* Had been drug free for \> 3 months
* Physically healthy and had all laboratory parameters within normal limits.
* Agree to participate in the study and provide informed consent

Exclusion Criteria:

* Had history of epilepsy, head trauma or other major neurological or medical diseases
* Had psychotic depression, bipolar I/II disorder, schizophrenia or any other psychotic disorder
* Moderate-severe suicidal risks
* Severe cognitive impairment
* Female subjects who were pregnant, or at risk of pregnancy or lactation
* Initiating or stopping formal psychotherapy within six weeks prior to enrollment
* Had a history of poor response to SSRIs or previously received electroconvulsive therapy
* Had a history of severe adverse reaction to SSRIs.
C: Inclusion Criteria:

* At the time of signing the informed consent form (ICF), participant must be a man or woman 18 (or older if the minimum legal age of consent in the country in which the study is taking place is greater than \[\>\]18) to 64 years of age, inclusive
* At the start of the screening/prospective observational phase, participant must meet the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnostic criteria for single-episode major depressive disorder (MDD) (if single-episode MDD, the duration must be greater than or equal to \[\>=\] 2 years) or recurrent MDD, without psychotic features, based upon clinical assessment and confirmed by the Mini-International Neuropsychiatric Interview (MINI)
* At the start of the screening/prospective observational phase, participant must have an Inventory of Depressive Symptomatology-Clinician rated ( IDS-C30) total score of greater than or equal to (\>=) 34
* At the start of the screening/prospective observational phase, participants must have had non-response (less than or equal to \[\<=25\] percent \[%\] improvement) to \>=1 but less than or equal to (\<=) 5 (if current episode is \>2 years, upper limit is applicable to only the last 2 years) oral antidepressant treatments taken at adequate dosage and for adequate duration, as assessed using the Massachusetts General Hospital - Antidepressant Treatment Response Questionnaire (MGH-ATRQ) and documented by medical history and pharmacy/prescription records, for the current episode of depression.

Participant is taking a different oral antidepressant treatment on the MGH-ATRQ for at least the previous 2 weeks at or above the minimum therapeutic dose

- The participant's current major depressive episode, depression symptom severity (Week 1 MADRS total score \>=28 required), and antidepressant treatment response in the current depressive episode, must be confirmed using a Site Independent Qualification Assessment

Exclusion Criteria:

* Participants who have previously demonstrated nonresponse of depressive symptoms to esketamine or ketamine in the current major depressive episode, to all 4 of the oral antidepressant treatment options available for the double-blind induction phase (i.e, duloxetine, escitalopram, sertraline, and venlafaxine extended release \[XR\]) in the current major depressive episode (based on MGH-ATRQ), or an adequate course of treatment with electroconvulsive therapy (ECT) in the current major depressive episode, defined as at least 7 treatments with unilateral/bilateral ECT
* Participant has received vagal nerve stimulation (VNS) or has received deep brain stimulation (DBS) in the current episode of depression
* Participant has a current or prior DSM-5 diagnosis of a psychotic disorder or MDD with psychotic features bipolar or related disorders (confirmed by the MINI), obsessive compulsive disorder (current only), intellectual disability (DSM-5 diagnostic codes 317, 318.0, 318.1, 318.2, 315.8, and 319), autism spectrum disorder, borderline personality disorder, antisocial personality disorder, histrionic personality disorder, or narcissistic personality disorder
* Participant has homicidal ideation/intent, per the investigator's clinical judgment, or has suicidal ideation with some intent to act within 6 months prior to the start of the screening/prospective observational phase, per the investigator's clinical judgment or based on the Columbia Suicide Severity Rating Scale (C-SSRS)
* Participants with history of moderate or severe substance or alcohol use disorder according to DSM-5 criteria
D: * INCLUSION CRITERIA:

Male or female subjects, 18-70 years of age.

Female subjects of childbearing potential must be using a medically accepted means of contraception.

Each subject must have a level of understanding sufficient to agree to all required tests and examinations.

Each subject must understand the nature of the study and must sign an informed consent document.

Subjects must fulfill the criteria bipolar I or II disorder, current episode depressed without psychotic features as defined in the Diagnostic and Statistical Manual (DSM-IV) based on clinical assessment and confirmed by the Structured Clinical Interview for DSM (SCID-P).

Subjects must have an initial score at Visit 1 and Visit 2 of at least 20 on the MADRS.

Current duration of depressive episode should be at least 4 weeks.

Subjects must have experienced, in the opinion of the investigator, at least one previous major depressive episode as defined in DSM-IV (not including the current major depressive episode).

EXCLUSION CRITERIA:

Presence of psychotic features.

Female subjects who are either pregnant or nursing.

Serious, unstable illnesses including hepatic, renal, gastroenterologic, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, or hematologic disease.

Subjects with uncorrected hypothyroidism or hyperthyroidism.

Clinically significant abnormal laboratory tests.

Current or past blood dyscrasia.

Documented history of hypersensitivity or intolerance to riluzole.

DSM-IV substance abuse or dependence within the past 90 days. No alcohol or recreational drug use will be permitted during the study.

Treatment with an injectable depot neuroleptic within less than one dosing interval between depot neuroleptic injections prior to visit 2.

Treatment with a reversible monoamine oxidase inhibitor (MAOI), guanethidine, or guanadrel within 1 week or with fluoxetine within 5 weeks prior to Visit 2.

Treatment with any other concomitant medication with primarily central nervous system (CNS) activity, other than specified in Appendix A.

Treatment with clozapine or electroconvulsive therapy (ECT) within 4 weeks prior to Visit 2.

Current diagnosis of schizophrenia or other psychotic disorder as defined in the DSM-IV.

Current Axis I Anxiety Disorder that is clinically significant.

Judged clinically to be at serious suicidal risk.

Answer: C