Psychosis presenting in childhood and adolescence has been a controversial topic throughout the history of the field of child psychiatry because of the conundrum of diagnostic pellucidity. As the essentiality of diagnostic precision apprises treatment as well as prognosis, a paramount question is whether the sundry psychoses of childhood are contiguous with the adult forms, or whether the symptoms labeled as psychotic in youth, categorically in prepubertal children, are precisely identically tantamount to those visually perceived in adults. Historically, the definition of psychosis in children and adolescents has been concretely nebulous because of perplexity regarding the developmentally felicitous role of imagination and fantasy in children and adolescents with and without psychiatric disorders. Formulations of childhood psychosis and psychosis were pristinely conceptualized as a component of the spectrum of the pervasive developmental disorders, but currently, symptoms of psychosis and definitions of psychotic disorders do not differ for children, adolescents, or adults in the Diagnostic and Statistical Manual of Noetic Disorders. The diagnosis of childhood psychosis raises a host of unresolved quandaries, despite the Diagnostic and Statistical Manual Of  Noetic Disorders, 4th edition, Text Revision (DSM-IV-TR) giving identical symptoms and definitions for children, adolescents, and adults. The fantasy lives of children, and issues of developing language and cognition (including retardation), all impair diagnostic precision, concretely when differentiating between childhood-onset schizophrenia (COS) bipolar affective disorder, major depressive disorder, and even obsessive-compulsive disorder and attention-deficit/hyperactivity disorder: the catch-all relegation, psychosis not otherwise designated (PNOS), is always available for conundra that prove unsolvable. Typical if nonpathognomonic features include neurocognitive difficulties. Multiple screening instruments and specialized versions of semistructured diagnostic interviews are available. Albeit smooth-pursuit ocular perceiver-tracking forms of kineticism may prove a genetic marker for COS, etiologies are liable to be oligogenetic rather than cognate to a single gene. No categorical biological markers or neuroimages have been identified. As such, psychoses may be indicative of a more general pattern of encephalon dysfunction. Drug treatments are largely predicated on the adult literature because of a dearth of controlled data below age 18. There are still no rigorous studies of psychosocial treatments and psychotherapy categorical to childhood psychosis.