The purpose of this study is to evaluate how well JNJ-54135419 works (efficacy) in addition to comprehensive standard of care (SoC) in rapidly reducing the symptoms of major depressive disorder (MDD, a mental disorder characterized by a persistent feeling of sadness and loss of interest in activities) as compared with psychoactive placebo (does not contain JNJ-54135419) plus SoC in adolescent participants with acute suicidal ideation or behavior.
Must meet diagnostic and statistical manual of mental disorders (5th edition) (DSM-5) diagnostic criteria for major depressive disorder (MDD) based upon clinical assessment and confirmed by the mini-international neuropsychiatric interview for children and adolescents (MINI-KID)
Must have a clinical global impression - severity of suicidality - revised (CGI-SS-R) score of "Markedly" or greater (that is, greater than or equal to [>=] 4) at both screening and baseline (predose) visits
Must have a children's depression rating scale - revised (CDRS-R) total score >= 58 at baseline (predose)
In the physician's opinion, acute psychiatric hospitalization is clinically warranted due to subject's acute suicidality
Participant has a current DSM-5 diagnosis of bipolar (or related disorders), intellectual disability, autism spectrum disorder, conduct disorder, oppositional defiant disorder
Participant currently meets DSM-5 criteria for borderline personality disorder
Participant has a current or prior DSM-5 diagnosis of a psychotic disorder, or MDD with psychosis
Participant has a history of seizure disorder