Childhood Onset Schizophrenia and Other Early-Onset Psychotic Disorders

Nitin Gogtay

Judith Rapoport

Background

Psychotic disorders are rare in children although transient psychotic phenomena are more common in healthy and mildly disturbed children than generally recognized (1,2,3). As is often the case with other very early onset illnesses, psychotic disorders in children are usually more severe than their adult counterparts (4), and the disruption of cognitive and social development and the burden to the family can be devastating. Systematic research in this area has been limited by diagnostic uncertainty and the general lack of knowledge about the psychotic processes in children (5).

History of Very Early Onset Psychoses

Although the existence of childhood schizophrenia was recognized early in the twentieth century (6), the term psychosis was used so broadly in children that a spectrum of behavioral disorders and autism were grouped together under the category of childhood schizophrenia (7). The landmark studies of Kolvin (1971) first established the clinical distinction between autism and other psychotic disorders of childhood (8). However, even today high rates of initial misdiagnosis remain due to symptom overlap, particularly for mood disorders, and the presence of relatively fleeting hallucinations and delusions in nonpsychotic pediatric patients (9,10). Anxiety and stress are probably the most common causes of hallucinations in preschool children, and the prognosis of these phenomena is usually benign (11). On the other hand, psychotic phenomena in school age children generally tend to be more persistent, and are more likely to be associated with drug toxicity or significant mental illness (2,3,12,52). Moreover, recent data from large birth cohort studies suggest that self-reported psychotic symptoms at age 11 years predicted a very high risk (odds ratio 16.4, confidence interval 3.9–67.8) of schizophreniform diagnosis at age 26 years, suggesting that psychotic symptoms probably exist as a continuous phenotype rather than an all-or-none phenomenon (14).

Childhood Schizophrenia— Diagnosis, Clinical Presentation, and Differential Diagnoses

Kolvin’s work established that children can be diagnosed with unmodified criteria for schizophrenia, although such cases are rare (15,16). Childhood-onset schizophrenia (COS) shows a pattern similar to that of poor outcome adult cases, and the psychosis of COS can usually be distinguished by its severe and pervasive nature and its nonepisodic, unremitting course (5). Additionally, these children show poorer premorbid functioning in social, motor, and language domains, learning disabilities, and disruptive behavior disorders (17,18,19), and although not reported in studies of the premorbid history of adult-onset schizophrenia (20,21), transient autistic symptoms such as hand flapping and echolalia in toddler years are common (17,22), probably reflecting more compromised early brain development.

Childhood-onset schizophrenia is rare and must be distinguished from several childhood conditions that can manifest with psychotic symptoms and/or deterioration in function:

Affective disorders: Hallucinations are relatively common in pediatric bipolar disorder and major depression (23,24). However, the psychotic symptoms in these conditions tend to be mood congruent and followup studies on this population generally suggest a stable clinical outcome (25,26,27,52).
Psychosis due to medical conditions, and substance abuse disorders should be carefully ruled out (29,30).
Pervasive developmental disorders and childhood disintegrative disorder can often be mistaken for psychosis, as they show severe impairment in reciprocal communication, social interactions, and odd stereotyped behaviors.
Conduct disorder and various other behavioral disturbances can be associated with hallucinations (28,29).
Atypical psychosis [provisionally labeled as Multi Dimensionally Impaired (MDI) by the NIMH group] is an important differential diagnosis and is described in detail below.

The Multi Dimensionally Impaired (MDI) Group

A sizeable, heterogeneous group of children referred to the NIMH childhood onset schizophrenia study over the past 15 years had transient psychotic symptoms and multiple developmental abnormalities, but were not adequately characterized by existing DSM-IV categories (31,32,33). In the DSM nosology these patients might be considered as having either psychosis NOS or mood disorder NOS.

The MDI group, although showing similarities with childhood onset schizophrenia, has distinct features which were used as the operational diagnostic criteria by the NIMH group, as listed below (31,32):