The characteristic symptoms of schizophrenia include delusions, or beliefs held contrary to all evidence; hallucinations, or distortions in the perception of reality; disorganized or incoherent speech; and extremely disorganized or catatonic behavior (i.e. physical immobility or excessive mobility). Children with schizophrenia may display a lack of emotional responsiveness (called blunted or flattened affect), a lack of motivation (called avolition) and a lack of voluntary speech (called alogia). Other symptoms may include strange eating rituals, irritability, or inappropriate emotions. A child will be diagnosed with schizophrenia only if his symptoms interfere with age-appropriate activities, and have been in evidence for at least 6 months.
Schizophrenia is very difficult to diagnose because other psychiatric disorders (bipolar disorder, OCD, depression, even substance abuse) can generate similar symptoms if they manifest in psychosis. It is possible children with schizophrenia will be falsely diagnosed with conduct disorder because paranoia makes them respond in hostile or oppositional ways.