The PANSS consisted of three subscales: a total of 30 symptom constructs. For each symptom construct, severity was rated on a 7-point scale, with a score of 1 (absence of symptoms) and a score of 7 (extremely severe symptoms). The PANSS total score was the sum of the rating scores for 7 positive scale items, 7 negative scale items, and 16 general psychopathology scale items from the PANSS panel. The PANSS total score ranged from 30 (best possible outcome) to 210 (worst possible outcome).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

Severity of illness for each participant was rated using the CGI-S, which was the key secondary efficacy endpoint. To perform this assessment, the study physician answered the following question: "Considering your total clinical experience with this particular population, how mentally ill is the participant at this time?" Response choices included: 0 = not assessed; 1 = normal, not at all ill; 2 = borderline mentally ill; 3 = mildly ill; 4 = moderately ill; 5 = markedly ill; 6 = severely ill; and 7 = among the most extremely ill participants.

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

PSP is a validated clinician-rated scale that measures personal and social functioning in 4 domains: socially useful activities (e.g. work and study), personal and social relationships, self-care, and disturbing and aggressive behaviors. Impairment in each of these domains was rated as absent, mild, manifest, marked, severe, or very severe. These ratings were then converted to a total score based on a 100-point scale using algorithms to identify the appropriate 10-point interval, and the rater's judgment to determine the total score within the 10-point interval. Participants with a PSP total score of 71 to 100 were considered to have mild functional difficulty. Scores of 31 to 70 represented manifest disabilities of various degrees and ratings of 1 to 30 indicated minimal functioning that required intense support and/or supervision.

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

PANSS consisted of three subscales: a total of 30 symptom constructs. For each construct, severity was rated on a 7-point scale, with a score of 1 (absence of symptoms) and a score of 7 (extremely severe symptoms). The PANSS positive subscale score was the sum of the rating scores for the 7 positive scale items from the PANSS panel. The 7 positive symptom constructs are delusions, conceptual disorganization, hallucinatory behavior, excitement, grandiosity, suspiciousness/persecution, and hostility. The PANSS positive subscale score ranged from 7 (best possible outcome) to 49 (worst possible outcome). The analysis of secondary endpoints was conducted if both comparisons of brexpiprazole 4 mg/day vs placebo and brexpiprazole 2 mg/day vs placebo of the primary endpoint were significant. Although only the comparison of brexpiprazole 4 mg/day vs placebo met the gatekeeping threshold in the primary analysis, statistical testing for the other doses was reported for information.

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

The PANSS consisted of three subscales: a total of 30 symptom constructs. For each symptom construct, severity was rated on a 7-point scale, with a score of 1 (absence of symptoms) and a score of 7 (extremely severe symptoms). The PANSS negative subscale score was the sum of the rating scores for the 7 negative scale items from the PANSS panel. The 7 negative symptom constructs: blunted affect, emotional withdrawal, poor rapport, passive apathetic withdrawal, difficulty in abstract thinking, lack of spontaneity and flow of conversation, stereotyped thinking. The PANSS negative subscale score ranged from 7 (best possible outcome) to 49 (worst possible outcome).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

The efficacy of trial medication was rated for each participant using the CGI-I. The study physician would rate the participant's total improvement whether or not it is due entirely to drug treatment. All responses were compared to the participant's condition at Baseline prior to the first dose of double-blind study medication. Response choices included: 0 = not assessed, 1 = very much improved, 2 = much improved, 3 = minimally improved, 4 = no change, 5 = minimally worse, 6 = much worse, and 7 = very much worse.

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

The response rate was defined as reduction of ≥30% from Baseline in PANSS Total Score or CGI-I score of 1 or 2.

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

Participants discontinued for lack of efficacy during the trial were reported here.

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

The PEC score consisted of five PANSS items: excitement (P4), hostility (P7), tension (G4), uncooperativeness (G8), and poor impulse control (G14). Each of the items were rated on a scale of 1 (absent) to 7 (extreme). The PEC scores ranged from 5 (not present) to 35 (extremely severe).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

Retrospective factor analyses have been performed in recent decades using scores for the 30 individual PANSS items to categorize symptoms into 5 dimensions. Collectively, these dimensions are referred to as the PANSS Marder Factor scores and include positive symptoms score, negative symptoms score, thought score, uncontrolled hostility/excitement, anxiety depression score. The positive factor score is the sum of the 8 components of the positive symptoms scale (range: 8 - best possible outcome to 56 - worst possible outcome).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

Retrospective factor analyses have been performed in recent decades using scores for the 30 individual PANSS items to categorize symptoms into 5 dimensions. Collectively, these dimensions are referred to as the PANSS Marder Factor scores and include positive symptoms score, negative symptoms score, thought score, uncontrolled hostility/excitement, anxiety depression score. The negative factor score is the sum of the 7 items of the negative subscale (range: 8 - best possible outcome to 56 - worst possible outcome).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

Retrospective factor analyses have been performed in recent decades using scores for the 30 individual PANSS items to categorize symptoms into 5 dimensions. Collectively, these dimensions are referred to as the PANSS Marder Factor scores and include positive symptoms score, negative symptoms score, thought score, uncontrolled hostility/excitement, anxiety depression score. The disorganized thoughts factor score is the sum of score from the 7 items on the disorganized thoughts subscale (range: 7 - best possible outcome to 49 - worst possible outcome).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

Retrospective factor analyses have been performed in recent decades using scores for the 30 individual PANSS items to categorize symptoms into 5 dimensions. Collectively, these dimensions are referred to as the PANSS Marder Factor scores and include positive symptoms score, negative symptoms score, thought score, uncontrolled hostility/excitement, anxiety depression score. The uncontrolled hostility/excitement factor score is the sum of score from the 4 items on the uncontrolled hostility/excitement subscale (range: 4 - best possible outcome to 28 - worst possible outcome).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.

Retrospective factor analyses have been performed in recent decades using scores for the 30 individual PANSS items to categorize symptoms into 5 dimensions. Collectively, these dimensions are referred to as the PANSS Marder Factor scores and include positive symptoms score, negative symptoms score, thought score, uncontrolled hostility/excitement, anxiety depression score. The anxiety/depression factor score is the sum of score from the 4 items on the anxiety/depression subscale (range: 4 - best possible outcome to 28 - worst possible outcome).

Efficacy sample consisted of all participants who received at least one dose of study medication and have Baseline and at least one Post-Baseline efficacy evaluation.