Opiate Suicide Study in Patients With Major Depression

Inclusion Criteria

• A subject will be eligible for inclusion only if all of the following criteria are met:
• Male or female, 18 to 70 years of age, inclusive, at screen.
• Able to read, understand, and provide written, dated informed consent prior to screening. Participants will be deemed likely to comply with study protocol and communicate with study personnel about adverse events and other clinically important information.
• Diagnosed with Major Depressive Disorder (MDD), single or recurrent or Bipolar-II Disorder and currently experiencing a Major Depressive Episode (MDE) of at least eight weeks in duration, prior to screening, according to the criteria defined in the Diagnosis and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision(DSM-IV-TR™). The diagnosis of MDD will be made by a site psychiatrist and supported by the Structured Clinical Interview for DSM-IV-TR™ (SCID-I/P).
• Has a history of TRD during the current MDE, as assessed by the investigator. TRD is defined as failure to achieve a satisfactory response (e.g., less than 50% improvement of depression symptoms), as perceived by the participant, to at least one "treatment course" of a therapeutic dose of an antidepressant therapy of at least 8 weeks duration. The adequacy of dose and duration of the antidepressant therapy will be determined as per the MGH ATRQ criteria. Participants must currently be on a stable (for at least 4 weeks) and adequate (according to the MGH ATRQ) dose of ongoing SSRI or SNRI antidepressant therapy, of which total duration must be at least 8 weeks. Participants may also have a history of intolerance to at least 2 antidepressant medications. These patients with the intolerance history will not be required to be currently taking an antidepressant medication.
• Meet the threshold on the total SSI score of >/=6 at screening visit.
• Participants must qualify as "Moderately Treatment Refractory" using the Maudsley staging method, which incorporates past treatments, severity of symptoms and duration of presenting episode.
• In good general health, as ascertained by medical history, physical examination (PE) (including measurement of supine and standing vital signs), clinical laboratory evaluations, and 3-lead electrocardiogram (ECG) if no evaluation available from the last 6 months.
• If female, a status of non-childbearing potential or use of an acceptable form of birth control per the following specific criteria:

a. Non-childbearing potential (e.g., physiologically incapable of becoming pregnant, i.e., permanently sterilized (status post hysterectomy, bilateral tubal ligation), or is post-menopausal with her last menses at least one year prior to screening); or b. Childbearing potential, and meets the following criteria: i. Childbearing potential, including women using any form of hormonal birth control, on hormone replacement therapy started prior to 12 months of amenorrhea, using an intrauterine device (IUD), having a monogamous relationship with a partner who has had a vasectomy, or is sexually abstinent.

ii. Negative urinary pregnancy test at screening, confirmed by a negative urinary pregnancy test at randomization prior to receiving study treatment.

iii. Willing and able to continuously use one of the following methods of birth control during the course of the study, defined as those which result in a low failure rate (i.e., less than 1% per year) when used consistently and correctly: implants, injectable or patch hormonal contraception, oral contraceptives, IUD, double-barrier contraception, sexual abstinence. The form of birth control will be documented at screening and baseline.

• Body mass index between 17-40kg/m2.
• Concurrent psychotherapy will be allowed if the type (e.g., supportive, cognitive behavioral, insight-oriented, et al) and frequency (e.g., weekly or monthly) of the therapy has been stable for at least three months prior to screening and if the type and frequency of the therapy is