An AE was any untoward medical occurrence in a participant who received study drug. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of study drug and up to 28 days after last dose that were absent before treatment or that worsened relative to pre-treatment state. AEs included both SAEs and non-SAEs.

The following laboratory parameters were analyzed: hematology (hemoglobin, hematocrit, red blood cell \[RBC\] count, RBC morphology, platelet count, white blood cell \[WBC\] count, total neutrophils, eosinophils, monocytes, basophils, lymphocytes); blood chemistry (blood urea nitrogen \[BUN\], creatinine, glucose, calcium, sodium, potassium, chloride, total bicarbonate, aspartate aminotransferase \[AST\], alanine aminotransferase \[ALT\], total bilirubin, alkaline phosphatase, uric acid, albumin, and total protein; urinalysis (pH, glucose, protein, blood, ketones, nitrites, leukocyte esterase, microscopy \[if urine dipstick was positive for blood, protein, nitrites or leukocyte esterase\]); others (coagulation panel, circulating immune complex, and complement activation).

Vital signs assessment included pulse rate and blood pressure. Criteria for vital sign values meeting potential clinical concern included: supine/sitting pulse rate \<40 or \>120 beats per minute (bpm); standing pulse rate \<40 or \>140 bpm; systolic blood pressure (SBP) of more than or equal to (\>=)30 millimeters of mercury (mm Hg) change from baseline in same posture or SBP \<90 mm Hg, diastolic blood pressure (DBP) \>=20 mmHg change from baseline in same posture or DBP \<50 mm Hg.

ECG parameters included PR interval, QRS interval, and QT interval. Criteria for ECG changes meeting potential clinical concern included: PR interval \>=300 milliseconds (msec) or \>=25% increase when baseline is \>200 msec and \>=50% increase when baseline is less than or equal to (\<=)200 msec; QRS interval \>=200 msec or \>=50% increase from baseline when baseline is less than or equal to 100 msec and \>=25% increase when baseline is \>100 msec; and QTcF \>=450 msec or \>=30 msec increase.

A full physical examination consisted of an examination of the abdomen, genitourinary and cardiovascular systems, lungs, lymph nodes, mouth, musculoskeletal and neurological systems, skin, extremities, head, ears, eyes, nose, throat and thyroid gland. Criteria for abnormal physical findings was based on the investigator's discretion and any new physical examination findings were documented as AEs. Only sites with at least 1 participant abnormality are reported.

Neurological examinations were done to the extent needed to assess the subject for any potential changes in neurological status, as determined by the investigator. Examinations included level of consciousness, speech, cranial nerves, motor, sensory, coordination, gait, and tendon reflexes. Only tests with at least 1 participant abnormality are reported.

The C-SSRS captures the occurrence, severity, and frequency of suicide-related thoughts and behaviors during the assessment period. C-SSRS assesses whether participant experienced the following: completed suicide; suicide attempt; preparatory acts towards imminent suicidal behavior; suicidal ideation; self-injurious behavior, no suicidal intent. The results presented are the number of participants with completed suicide or non-fatal suicide events or behaviors. Worsening of suicidal ideation was an increase in severity of suicidal ideation from baseline.

Brain MRIs were collected to assess for potential drug-related changes that might have constituted a safety concern. Findings suggestive of either vasogenic edema or intracranial hemorrhage were to be reported as AEs of special circumstance.

Criteria for potential clinical concern in vital signs included: supine/sitting pulse rate of less than (\<) 40 or more than (\>) 120 beats per minute (bpm), and standing pulse rate of \<40 or \>140 bpm; systolic blood pressure (SBP) of more than or equal to (\>=)30 millimeters of mercury (mm Hg) change from baseline in same posture and \<90 mm Hg; diastolic blood pressure (DBP) \>=20 mm Hg change from baseline in same posture and \<50 mm Hg. Only supine vital signs were planned for this study. Unplanned sitting vital signs were collected only in the 8/mg and placebo groups and also reported.

The C-SSRS assessed whether the participant experienced the following: completed suicide (1), suicide attempt (2) (response of "Yes" on "actual attempt"), preparatory acts toward imminent suicidal behavior (3)("Yes" on "preparatory acts or behavior"), suicidal ideation (4) ("Yes" on "wish to be dead", "non-specific active suicidal thoughts", "active suicidal ideation with methods without intent to act or some intent to act, without specific plan or with specific plan and intent), any suicidal behavior or ideation, self-injurious behavior (7)("Yes" on "Has participant engaged in non-suicidal self-injurious behavior").

Brain MRIs were collected during the course of study to assess for any potential drug-related changes that might have constituted a safety concern for study participants. Findings suggestive of either vasogenic edema (VE) or intracranial hemorrhage represented adverse events of special circumstance and were to be reported immediately.

VE of the brain, identified via MRI, was identified as an adverse event of special circumstance.

Criteria for ECG values of potential clinical concern are: interval between the start of the ECG P wave and the start of the QRS complex corresponding to the time between onset of atrial depolarization and onset of ventricular depolarization (PR): \>= 300 milliseconds (msec), and \>=25% increase when baseline \>=200 msec/ \>=50% increase when baseline less than or equal to (\<=) 200 msec; time from ECG Q wave to the end of S wave corresponding to ventricular depolarization (QRS): \>=200 msec, and \>=25% increase when baseline \>100 msec/ \>=50% increase when baseline \<=100 msec; QTc using Fridericia's formula (QTcF) interval: 450 to \<480 msec, \>=480 msec; QTcF change from baseline: 30 to \<60 msec, and \>=60 msec.