The differential diagnosis of childhood schizophrenia includes mood
and anxiety disorders (eg, obsessive compulsive disorder), seizure
disorder, psychotic depression, mania, and conduct disorder. Mood
and anxiety disorders often coexist with schizophrenia and may alter
the clinical presentation. Occasionally, seizure disorders may present
in ways suggestive of psychosis or schizophrenia. Childhood-onset
schizophrenia should be differentiated from the mood disturbances
that are seen in psychotic depression or mania. Sometimes, children with
obsessive compulsive disorder may exhibit ideas that are difficult
to distinguish from delusions; however, an affected child usually is
cognizant of the irrational nature of such ideas. Children with
conduct disorder may exhibit hallucinations. Hallucinations occasionally
occur as an isolated symptom in preschool children, particularly
with stress. In school-age children, psychotic symptoms are more
worrisome and likely to be associated either with serious psychopathology
or substance abuse.