Introduction The diagnosis of schizophrenic disorder in children and adolescents is often complex and challenging. The symptomatic overlap between schizophrenia and other psychotic disorders has produced high rates of misdiagnosis. The clinical expression and progression of early onset schizophrenia is affected by maturation processes. Thus, schizophrenia in the paediatric population may vary from adult-onset form presentation because of developmental factors. Schizophrenia diagnosis can be complicated by difficulties distinguishing between immature response, typical in younger children, and pathological symptoms such as thought disorders, negative symptoms and delusions. Differential diagnosis is complicated by the presence of disorders that share common symptoms and are frequently associated with schizophrenia. Correct assessment procedures and early identification of the disorder may allow prompt and adequate treatment for reducing the natural progressive impairment seen in these patients. Objective The aim of this article is to review recent research and current concepts relating to phenomenology, diagnosis and the adequate assessment of earlyonset schizophrenia. We will examine the developmental precursors of child and adolescent schizophrenia. Clinical presentation during premorbid, prodromic and acute phases will be investigated. Moreover, our report will summarise what is currently known about the short and long-term outcome in paediatric and adolescent schizophrenia. Method A narrative review has been carried out of scientific literature using the Medline database to identify recent research related to premorbid course, phenomenology, diagnosis, assessment and outcome of early-onset schizophrenia. Moreover, we reviewed articles related to neurobiological continuity between early-onset and adult-onset schizophrenia. We selected literature between January 1994 and April 2007. Results We found scientific evidence that supports the identification of prodromal presentation, onset, and progression of child and adolescent schizophrenia. The clinical phenomenology of symptoms such as delusions, hallucinations, formal thought disorder and negative symptoms, are defined (Tables III, IV). The insidious onset in children (75%), the high rates of developmental abnormalities and the high prevalence of comorbid disorders delay the recognition of the syndrome (Tables V, VI). Elementary auditory hallucinations are the most frequent positive symptoms. Delusions are less complex than in the adult form of schizophrenia, and are usually thematically-related to childhood. Negative symptoms, mostly flat or inappropriate affect, show high prevalence rates. Marked cognitive and social deterioration from previous functioning levels is described in all these children. Outcome is impaired in about 50% of children and adolescents with schizophrenia. The main diagnostic challenge is differential diagnosis between early-onset schizophrenia, mood and emotional disorders, with the overlap with bipolar disorders with psychotic symptoms, severe obsessive-compulsive disorder, and posttraumatic stress disorder as confounders (Table IX). Conclusions EOS is a rare form of schizophrenia that is clinically and neurobiologically continuous with the later-onset disorder. Children and adolescents with schizophrenia have a quite similar clinical presentation with more severe premorbid symptoms and poorer prognosis, compared with adult-onset schizophrenia. Premorbid abnormalities and the insidious prodromic phase are the main reasons for misdiagnosis. Early identification and assessment of this disorder may help children to receive correct treatment. Although there is compelling evidence that schizophrenia can be diagnosed in children and adolescents from the age of seven using unmodified adult criteria, the predictive validity of these early diagnoses is partially unknown. Only once we begin to understand the early clinical presentations of schizophrenia, we will be able to develop early intervention and preventive treatment strategies for reducing progressive impairment and develop better outcomes.
