Study to Evaluate the Performance Validity and Test-Retest Reliability of a Computer-Administered Cognitive Test Battery in Participants With Major Depressive Disorder (MDD)

Inclusion Criteria:

- a) Substudy A and Main Study:

- Primary diagnosis of Major depressive disorder (MDD), made or confirmed by the
investigator according to the Diagnostic and Statistical Manual of Mental Disorders-5
(DSM-5) criteria

- Demonstrated an adequate clinical response within the past 24 months, and is currently
maintaining this response, to a stable oral antidepressant treatment regimen of no
more than 2 of the following: selective serotonin reuptake inhibitor (SSRI),
serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressants, in any formulation
(fluvoxamine, citalopram, duloxetine, escitalopram, fluoxetine, milnacipran,
levomilnacipran, paroxetine, sertraline, venlafaxine, desvenlafaxine, vilazodone, or
vortioxetine), or bupropion antidepressants, without any dosing changes for the most
recent 6 weeks. The dose and duration of treatment will be documented by the
investigator using the Massachusetts General Hospital Antidepressant Treatment
Response Questionnaire (MGH-ATRQ) and verified against the available medical and
pharmacy records or medication bottles/package labels

- Required to have a Montgomery-Asberg Depression Rating Scale (MADRS) total score of
less than or equal (<=)17 at screening and baseline (Test Day 1) visits as well as
less than or equal (<=)19 during subsequent testing days (main study). Participants
are also required to have a Clinical Global Impression - Severity (CGI-S) total score
of <=3 during testing days (main study)

- Must have adequate visual and hearing acuity to perform all aspects of the cognitive
and functional assessments as determined during physical examination

- b) Substudy B (Healthy Participants):

- Must be healthy on the basis of physical examination, vital signs examination, and
medical history performed at screening. This determination must be recorded in the
participant's source documents and initialed by the investigator

- Body mass index (weight [kilogram (kg)]/height^2 [meter (m)]^2) between 18 and 30
kg/m2 (inclusive)

- Blood pressure (after the participant is sitting for 5 minutes) between 90 and 140
millimeter of mercury (mmHg) inclusive, systolic, and no higher than 90 mmHg diastolic

- Must sign an Informed consent form (ICF) indicating that he or she understands the
purpose of, and procedures required for, the study and is willing to participate in
the study

Exclusion Criteria:

- a) Substudy A and Main Study:

- Has any of the following acute or chronic psychiatric conditions, according to
Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) criteria: Major
depressive disorder (MDD) with psychotic features (lifetime), bipolar disorder
(including lifetime diagnosis), obsessive-compulsive disorder, post-traumatic stress
disorder, borderline personality disorder, anorexia nervosa, schizophrenia,
schizoaffective disorder, or minor and major neurocognitive disorders (including
dementia)

- History of any acute or chronic neurological condition (for example (eg), stroke,
epilepsy, Parkinson's disease)

- b) Substudy B (Healthy Participants):

- History of drug or alcohol abuse, with a severity of at least moderate or severe,
according to DSM-5 criteria, within 6 months before screening or positive test
result(s) for alcohol or drugs of abuse (including barbiturates, opiates, cocaine,
cannabinoids, amphetamines and benzodiazepines) at screening or admission on Day 1

- Participant has clinically significant liver or renal insufficiency; cardiac,
vascular, pulmonary, gastrointestinal, endocrine, neurologic, hematologic,
rheumatologic, psychiatric, or metabolic disturbances. A significant primary sleep
disorder is exclusionary, including primary insomnia and hypersomnia, narcolepsy,
breathing-related sleep disorders, circadian-rhythm sleep disorders, and dyssomnias
not otherwise specified

- Has any condition for which, in the opinion of the investigator, participation would
not be in the best interest of the participant (for example, compromise the
well-being) or that could prevent, limit, or confound the protocol-specified
assessments