Kraeplin’s (1899) description of “dementia praecox” (what today is termed schizophrenia) was a watershed in psychiatric taxonomy. He explicitly noted that in some cases, onset was in childhood, and a downward extrapolation of the concept to children (“dementia praecossisma”) quickly followed. Severe psychiatric disturbance in childhood became equated with schizophrenia. Kanner’s description of the syndrome of infantile autism was taken by some as a description of the first manifestations of schizophrenia in infants and young children. However, with the pioneering work of Kolvin (1971), Rutter (1972), and others, it became clear that autism (see Chapter 4) is quite different from schizophrenia of childhood onset and was, if
anything, much less common than autism. As a result, a category for childhood schizophrenia (which before the DSM-III in 1980 included what would now be termed autistic disorder) was dropped, and infantile autism was officially recognized.

The DSM-IV-TR defines schizophrenia in basically the same way for children as for adolescents and adults. The DSM-IV-TR definition includes the various signs and symptoms traditionally associated with schizophrenia. These include both positive and negative symptoms (i.e., hallucinations as well as flattening of affect). By definition, the condition must be present for at least 6 months (it is noted that treatment may shorten the active psychotic phase) and must cause dysfunction in expected levels of functioning. For children, this can take the form of failure to achieve expected academic or social skills (i.e., rather than being restricted to a loss of skill). By definition, the disorder is not better accounted for by a mood disorder or schizoaffective disorder or by a general medical condition or substance abuse. A diagnosis of autism or pervasive development disorder can only be made if hallucinations and delusions are prominent for at least 1 month (or less if successfully treated). It is possible to specify various subtypes of the disorder (e.g., paranoid, disorganized, catatonic, undifferentiated) as well as the potential for some additional diagnostic codes (e.g., specifying course after 1 year). Other conditions included in this section of DSM-IV-TR include schizophreniform disorder (which is similar to schizophrenia except a decline in function is not required, and symptoms last from one to 6 months). Apart from psychotic disorder not otherwise specified (NOS), the other disorders in this group are rarely diagnosed in children. The DSM-IV-TR notes that late adolescent onset is frequent but that onset before adolescence is rare, particularly before puberty. It also notes that although the essential features are similar in children, adolescents, and adults with the condition, children may have less elaborated hallucination and delusions and that difficulties with language or attention or other developmental problems can complicate the diagnosis. Younger children may also be less likely to exhibit some of the “negative” symptoms. Incoherence and poverty of thinking are also somewhat less common than in adults.

Several different patterns of onset have been identified. These include a pattern of acute onset, another with gradual onset, and finally a pattern that includes a gradual onset followed by acute exacerbation of symptoms. The insidious onset pattern is more common. Sometimes symptoms emerge in a child who has previously had other developmental or behavioral problems. These can take the forms of developmental disorders (e.g., of learning or language or of the disruptive behavior disorders). Sometimes autistic-like symptoms are reported retrospectively (e.g., echolalia or hand flapping), but these tend to be of brief duration. Social oddity is also sometimes noted. Several groups have now confirmed these various premorbid features in many cases.

Auditory hallucinations are reported most frequently (˜80% of cases). As with adults, the content might include voices, often with persecutory content, commenting about the child. Somatic and visual hallucinations are less frequent. The content of the hallucinations is usually less elaborate in children and often reflects age-appropriate concerns (e.g., monsters or toys rather than more sexual themes). In childhood schizophrenia, auditory hallucinations are most consistently reported.

Delusions in children with schizophrenia are often less bizarre and systematic than those observed in adults. There may be concerns with thought broadcasting, thought insertion, and thought withdrawal.

Among school-age children, schizophrenia is relatively rare. Although solid epidemiologic data are critically needed, the childhood form of the disorder is probably 50 times less frequent than adult-onset schizophrenia. Clearly, the rate increases with age with onset frequent in adolescence. The condition appears to be somewhat more common in boys, particularly with younger children. As with adult schizophrenia, boys also appear to have an earlier onset than girls. Also, as with adults, there is probably some bias for increased rates in families with lower socioeconomic status.

As might be expected, it appears that the familial risk for schizophrenia and schizophreniclike illness is greater in childhood onset cases, with higher rates of cytogenetic abnormalities than seen in adults. Many potential candidate genes have been identified in adults and may be operative in childhood schizophrenia as well, although small sample sizes can complicate genetic studies. Associations have been reported with various conditions, including Smith-Magenis syndrome (17p11.2del), and 15q11-q13 deletions or duplications as well as with the 22q11 deletion syndrome (22q11DS) the velocardiofacial syndrome, which is associated with a high risk for schizophrenia. Mosaic Turner’s syndrome has also been noted at a higher than expected rate in the National Institute of Mental Health (NIMH) series of cases (see Gogray and Rapoport, 2007).

Various studies have examined the neuropsychological correlates of childhood-onset schizophrenia. Children with schizophrenia have more difficulty with tasks that involve greater attention, fine motor coordination, and working memory. Attentional difficulties have been explored using Event Related Potentials, showing decreased early receptor potential amplitude when children are engaged in these tasks; these results are similar to those seen in adults.

The NIMH group has looked for various risk factors associated with schizophrenia in adults within their childhood-onset sample. Interestingly, they failed to find increased obstetric risk (relative to healthy sibling control subjects), although there was a suggestion of differences in smooth pursuit eye movements. As with adult-onset schizophrenia, there appeared to be a significant genetic component, with higher than expected rates of schizophrenia spectrum disorders in family members. In their samples, the NIMH group assessed neurocognitive functioning and found that siblings of individuals with childhood-onset schizophrenia had poorer performance on a battery of neuropsychological assessments than community control subject. However, the rates of neuropsychological abnormalities did not differ between childhood- and adult-onset schizophrenia.

Neuroimaging studies have been conducted in individuals with childhood-onset schizophrenia and fairly consistently reveal increased volume of the lateral ventricles along with reduced gray matter but with increased volume of the basal ganglia. Some of the observed changes may, however, relate to medication effects). The longitudinal studies of the NIMH cohort of cases have been particularly helpful in document progressive changes over a period of several years.