Overview Schizophrenia and other psychotic disorders are medical illnesses that result in strange or bizarre thinking, perceptions like sight, sound, behaviours, and emotions. Psychosis is a brain-based condition that is made better or worse by environmental factors like stress. Children and youth who experience psychosis often say "something is not quite right" or can't tell if something is real or not real. It is a rare psychiatric illness in young children, although not uncommon and is hard to recognize in its early phases. Childhood Onset Most children with schizophrenia show delays in language and other functions long before their psychotic symptoms e.g. hallucinations, delusions, and disordered thinking, appear. In the first years of life, about 30% of these children have transient symptoms of pervasive developmental disorder, such as rocking, posturing, and arm flapping. Childhood-onset of psychosis may present with poor motor development, suc...