Advanced Reading: Understanding Schizophrenia and Psychoses

INTRODUCTION

Background: Childhood-onset schizophrenia is a severe disorder that usually is chronic and persistently disabling. The definition of childhood schizophrenia has changed over time. In the first 2 editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM), autistic disorder and childhood-onset schizophrenia were listed together as childhood psychoses. In the third edition of the DSM (DSM-III), autism was listed separately, and childhood-onset schizophrenia was incorporated into the general heading of schizophrenia. According to the fourth edition of the DSM (DSM-IV), the criteria for childhood-onset schizophrenia and adult schizophrenia are synonymous except for 1 potential modification for children (ie, in childhood-onset schizophrenia, the failure to meet expected social or academic milestones may be present rather than a deterioration in functioning).

Pathophysiology: Most psychological, pharmacologic, and neuroimaging studies of childhood-onset schizophrenia have suggested dysfunction in the prefrontal cortex and limbic system. The neurotransmitter implicated in the pathophysiology of schizophrenia is dopamine. Drugs increasing dopaminergic activity may induce a schizophreniform psychosis, and drugs that block postsynaptic D2 receptors help alleviate symptoms of schizophrenia. Other neurotransmitters also may be involved in the pathophysiology of schizophrenia. Glutamate has been implicated based in part on the production of psychotic symptoms by phencyclidine and the presence of NMDA receptor dysfunction. Serotonin may be important. The new atypical antipsychotic drugs have prominent serotonergic effects.

Frequency:

• In the US: Childhood-onset schizophrenia is a rare disorder. In preadolescents, estimated prevalence is less than 1 in 10,000. The number of new cases increases significantly during late adolescence, reaching an approximate prevalence of 1% for later onset schizophrenia.

• Internationally: No studies of prevalence of childhood-onset schizophrenia in underdeveloped countries exist. Schizophrenia with an onset later in life appears to have an equal prevalence in countries around the world, with a possible increased prevalence in urban populations.

Mortality/Morbidity: An increased risk of death from suicide is present in patients with schizophrenia. In the larger follow-up studies of childhood-onset schizophrenia, the mortality rate from suicide is 5-11%. In follow-up studies, more than one half of children with schizophrenia have persistent severe impairment in social skills and limitations in academic and occupational achievement.

Race: No studies exist of childhood-onset or adult-onset schizophrenia that allow comparisons based on race or ethnicity, nor do studies exist of prevalence in underdeveloped nations.

Sex: Most studies demonstrate a male-to-female ratio averaging 1.5-2:1.

Age: In a child younger than 13 years, onset of schizophrenia is rare and generally is insidious, carrying a worse prognosis. Onset of the disorder in the adolescent years is more common and may have an acute or insidious onset. In general, the earlier the onset of schizophrenia, the poorer the outcome.

CLINICAL

History: Most children who develop schizophrenia have disturbances of behavior and cognition prior to the onset of characteristic symptoms of psychosis. Delays in speech and language and delays in acquisition of motor milestones are noted in approximately one half of these children. Children who develop schizophrenia have higher rates of impaired social skills and school achievement prior to presenting signs of schizophrenia. Approximately one third of the children will have symptoms of inattention, hyperactivity, aggression, or rages. One half of these children have received prior diagnoses, including pervasive developmental disorders (PDDs), attention deficit/hyperactivity disorder (ADHD), and internalizing disorders (eg, bipolar disorder, depression, anxiety disorders). In one recent study, psychotic symptoms appeared, on average, 2 1/2 years after initial clinical presentation and the diagnosis of schizophrenia was made, a mean of 2 years after the onset of psychosis.

• The DSM-IV criteria for schizophrenia require at least 2 characteristic symptoms present for most of a 1-month period.

• The child fails to achieve expected social or academic milestones or demonstrates significant deterioration of functioning.

• Impairment should have lasted at least 6 months, including 1 month when characteristic symptoms are present.

• Diagnosis requires the exclusion of mood disorders with psychotic features (bipolar disease), substance-induced psychotic disorder, and psychosis due to a medical condition.

   

• If the child has a prior diagnosis of a PDD, a period of at least 1 month must pass, during which the child experiences hallucinations or delusions.

• All of the characteristic symptoms of schizophrenia have been described in persons with childhood-onset schizophrenia. Ballageer et al found that bizarre behavior and negative symptoms were more common in individuals with adolescent-onset schizophrenia compared with those with onset during the adult years.

• Approximately one half of children with schizophrenia have a formal thought disorder, although assessment may be more difficult in children than in adults.

   

  • Caplan and associates have demonstrated that loose associations and illogical thinking can be documented reliably.

     

  • Poverty of speech was not documented.

• In comparison to adults with schizophrenia, children with schizophrenia less often have catatonia.

   

• Changes in affect are common, with blunting or inappropriate affect observed in approximately two thirds of children with schizophrenia.

• Cognitive functioning often is impaired at the onset of childhood schizophrenia.