An Exploratory Multicenter, Double-Blind, Diphenhydramine- and Placebo-Controlled Safety, Efficacy and Biomarker Study with JNJ-42847922 in Subjects with Major Depressive Disorder.

1. Subjects must be men or women, 18 to 64 years of age, inclusive.
2. Before randomization, a woman must be either:
- Not of childbearing potential: postmenopausal (>45 years of age with amenorrhea for at least 12 months, or any age with amenorrhea for at least 6 months and a serum follicle stimulating hormone (FSH) level >40 IU/L); permanently sterilized (e.g., tubal occlusion, hysterectomy, bilateral salpingectomy); or otherwise be incapable of pregnancy
- Of childbearing potential and practicing a highly effective method of birth control consistent with local regulations regarding the use of birth control methods for subjects participating in clinical studies (i.e., one that results in a less than 1% per year failure rate when used consistently and correctly): e.g., established use of oral, injected or implanted hormonal methods of contraception; placement of an intrauterine device (IUD) or intrauterine system (IUS) in combination with barrier methods: condom with spermicidal foam/gel/film/cream/suppository or occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/suppository; male partner sterilization (the vasectomized partner should be the sole partner for that subject); true abstinence (when this is in line with the preferred and usual lifestyle of the subject). Women must agree to continue using these methods of contraception throughout the study and for at least 3 months after receiving the last dose of study medication.
Note: If the childbearing potential changes after start of the study (e.g., woman who is not heterosexually active becomes active) a woman must begin a highly effective method of birth control, as described above.
3. BMI must be between 18 and 30 kg/m2 inclusive (BMI=weight/height2)
4. Subjects must be physically healthy / medically stable on the basis of clinical laboratory tests, medical history, vital signs, and 12-lead ECG performed at screening. If the results of the serum chemistry panel, hematology, or urinalysis are outside the normal reference ranges, retesting of an abnormal lab value(s) that may lead to exclusion will be allowed once during the screening phase. A retest of an abnormal ECG value values will be allowed once in the screening phase. Blood pressure will be the average of
2 measurements.
• The subject may be included only if the investigator judges the abnormalities or deviations from normal to be not clinically significant or to be appropriate and reasonable for the population under study. This determination must be recorded in the subject's source documents and initialed by the investigator.
5. Population specific:
• Subject must meet the DSM-IV or 5 diagnostic criteria for MDD (International Classification of Diseases (ICD)-code F32.x and F33.x), without psychotic features, and confirmed by the MINI 6.0.
• Subject must have an IDS-C30 total score >= 30.
• Subject is either currently antidepressant naive or currently being treated with a maximum of two concurrent antidepressants (refer to list of allowed antidepressants in Attachment 1). If the subject is currently treated with antidepressants, they have to be given at an optimal dose and for at least 4 weeks, but not longer than 24 weeks with a suboptimal response (defined as an IDS-C30 total score >= 30).
6. A man who is sexually active with a woman of childbearing potential and has not had a vasectomy must agree to use a barrier method of birth control e.g., either condom with spermicidal foam/gel/film/cream/suppository or partner with occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/suppository, and all men must also not donate sperm during the study and for 3 months after receiving the last dose of study drug.
7. Subject must be willing and able to adhere to the prohibitions and restrictions specified in this protocol.
8. Each subject must sign an ICF indicating that he or she understands the purpose of and procedures required for the study.

Any potential subject who meets any of the following criteria will be excluded from participating in the study. The subject will be excluded if he or she:;1. Has current signs/symptoms of, liver or renal insufficiency; hypothyroidism or hyperthyroidism (a normal thyroid-stimulating hormone [TSH] is required at screening; subjects with hyperthyroidism who are on stable treatment with normal TSH may participate but subjects with thyroid supplementation for antidepressant purposes are not allowed in the study), significant cardiac, vascular, pulmonary, gastrointestinal, endocrine, neurologic, hematologic, inflammatory (e.g., rheumatoid arthritis, inflammatory bowel disease, Crohn*s disease), or metabolic disturbances. Subjects with diabetes mellitus (type I and II) are not allowed to participate in the study.;2. Is pregnant or breast feeding.;3. Subject has a history of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy that in the opinion of the investigator, with concurrence with the sponsor's study responsible physician, is considered cured with minimal risk of recurrence).
4. Has a primary DSM (4th or 5th edition) diagnosis of general anxiety disorder (GAD), panic disorder, obsessive compulsive disorder (OCD), posttraumatic stress disorder (PTSD), anorexia nervosa, or bulimia nervosa. Subjects with comorbid GAD, social anxiety disorder (SAD), or panic disorder for whom MDD is considered the primary diagnosis are not excluded.;5. Has a length of current major depressive episode (MDE) >24 months despite adequate treatment.;6. 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.;7. Has a current diagnosis of a psychotic disorder, MDD with psychosis, bipolar disorder, an eating disorder, mental retardation, cluster B personality disorder (e.g., borderline antisocial, narcissistic personality disorders), narcolepsy, obstructive sleep apnea/hypopnea (apnea/hypopnea index >10), central sleep apnea, sleep-related hypoventilation, circadian rhythm sleep-wake disorders, restless legs syndrome (periodic leg movements with arousal index >15), substance/medication-induced sleep disorder or parasomnias (NREM sleep arousal disorders, nightmare disorder, REM sleep behavior disorder).;8. Has a current or recent history of clinically significant suicidal ideation within the past 6 months, corresponding to a score of 4 (active suicidal ideation with some intent to act, without specific plan) or 5 (active suicidal ideation with specific plan and intent) for ideation on the C-SSRS, or a history of suicidal behavior within the past year, as validated by the C-SSRS at screening or Day 1. Subjects with a prior suicide attempt of any sort, or prior serious suicidal ideation/plan > 6 months ago, should be carefully screened for current suicidal ideation and only included at the discretion of the investigator.;9. Subject has received an investigational drug (including investigational vaccines) or used an invasive investigational medical device within 60 days before the planned first dose of study drug, or has participated in 2 or more interventional clinical studies in the previous
1 year, or is currently enrolled in an interventional study.

10. Subject is a man who plans to father a child while enrolled in this study or within 3 months after the last dose of study drug.;11. Subject has a history of hepatitis B surface antigen (HBsAg) or hepatitis C antibody (anti-HCV) positive, or other clinically active liver disease, or tests positive for HBsAg or anti-HCV at Screening.;12. Subject has a history of human immunodeficiency virus (HIV) antibody positive, or tests positive for HIV at Screening.;13. Subject has a history of drug or alcohol abuse or dependence according to DSM-IV or 5 criteria, except nicotine or caffeine, within 6 months before Screening. However, subjects 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.;14. Subject has positive test result(s) for alcohol or drugs of abuse (including barbiturates, methadone, opiates, cocaine, cannabinoids, amphetamine/methamphetamine, benzodiazepines and ecstasy) at Screening.;- Subjects with a positive alcohol or drug screen at Screening may have the test repeated once during the screening phase, based on the investigator's discretion. This determination, and the reason for permitting a repeat test, must be recorded in the subject's source documents and initialed by the investigator. A positive, repeat alcohol or drug screen is exclusionary.;15. Subject has used:;- Monoamine oxidase inhibitors (MAOIs) within 12 weeks before screening
- A known inhibitor or inducer of CYP3A4 or CYP2C9 activity (e.g., erythromycin, clarithromycin, ketoconazole, itraconazole) within 14 days or a period less than
5-times the drug*s half-life, whichever is longer, before the first study drug administration on Day 1
- St. John*s wort, ephedra, ginkgo, ginseng, or kava within 2 weeks before screening.;16. Subject is unable to stop the following medication from screening and throughout the study:
- Any hypnotics including but not limited to:
- Benzodiazepines
- Sedating antihistamines, including chronic use of diphenhydramine.
- Zolpidem, zoplicon, eszopiclone and ramelteon
- S-adenosyl methionine (SAMe)
- Melatonin
- Antipsychotic drugs (D2-antagonists)
- Lithium and other mood stabilizers
- Opiates
- Drugs which are primarily metabolised by CYP2D6, such as metoprolol and venlafaxine.;17. Is unwilling or unable to undergo multiple venipunctures because of poor tolerability or lack of easy access.;18. Has a contra-indication for the use of diphenhydramine.;19. Is not able to swallow capsules whole.

20. Is unable to read and understand the consent forms and patient reported outcomes, complete study-related procedures, and/or communicate with the study staff.;21. Subject has any condition for which, in the opinion of the investigator, participation would not be in the best interest of the subject (e.g., compromise the well-being) or that could prevent, limit, or confound the protocol-specified assessments.;22. Subject has had major surgery, (e.g., requiring local or general anesthesia) within 12 weeks before screening, or will not have fully recovered from surgery, or has surgery planned during the time the subject is expected to participate in the study.;23. Is a vulnerable subject (e.g., a person kept in detention).;24. Subject is an employee of the investigator or study site, with direct involvement in the proposed study or other studies under the direction of that investigator or study site, as well as family members of the employees or the investigator.;NOTE: Investigators should ensure that all study enrollment criteria have been met at screening. If a subject's status changes (including laboratory results) after screening but before first dose of study drug is given such that they now meet an exclusion criterion, they should be excluded from participation in the study.