Study of Brexpiprazole as Adjunctive Treatment of Sleep Disturbances in Patients With Major Depressive Disorder

Inclusion Criteria - at Screening:

- The patient has a Major Depressive Episode (MDE) associated to Major Depressive
Disorder (MDD), diagnosed according to Diagnostic and Statistical Manual of Mental
Disorders, 4th edition, Text Revision (DSM-IV-TR™). The current MDE should be
confirmed using the Mini International Neuropsychiatric Interview (MINI).

- The patient has an inadequate response to at least one antidepressant treatment
(including the treatment the patient is taking at screening) in the current MDE, as
documented by self-report as less than a pre-defined response on the Massachusetts
General Hospital Antidepressant Treatment Response Questionnaire (ATRQ).

- The patient has a pre-defined Montgomery Aasberg Depression Rating Scale (MADRS)
total score, and a pre-defined Clinical Global Impression - Severity of Illness
(CGI-S) score at screening, and has had the current MDE for ≥10 weeks.

- The patient is currently treated for the current MDE with an adequate selective
serotonin reuptake inhibitor (SSRI) or a serotonin-norepinephrine reuptake inhibitor
(SNRI) antidepressant treatment for ≥6 weeks, at the same dosage for ≥2 weeks.

- The patient has sleep disturbances (difficulty falling asleep and/or difficulty
staying asleep and/or problem waking up too early) confirmed by a pre-defined
Insomnia Severity Index (ISI) score.

- The patient agrees to protocol-defined use of effective contraception.

Entry Criteria to Treatment Period (Baseline Visit):

- The patient still fulfils DSM-IV-TR™ criteria for MDE.

- The patient received the same SSRI or SNRI antidepressant treatment at adequate dose
during the entire lead-in period.

- The patient has a pre-defined MADRS total score.

- The patient's improvement in the MADRS total score is a pre-defined percentage
compared to screening.

- The patient has a pre-defined Clinical Global Impression - Global Improvement (CGI-I)
score.

- The patient has sleep disturbances (difficulty falling asleep and/or difficulty
staying asleep and/or problem waking up too early) confirmed by a pre-defined ISI
score.

- The patient has sleep disturbances confirmed by pre-defined Latency to Persistent
Sleep (LPS) and pre-defined Sleep Efficiency (SE).

Exclusion Criteria:

- The patient is, in the investigator's opinion, unlikely to comply with the protocol
or is unsuitable for any reason.

Other inclusion and exclusion criteria may apply.