Early-onset schizophrenia in children with mental retardation: diagnostic reliability and stability of clinical features.

OBJECTIVES

To investigate the presentation of early-onset schizophrenia in children with mental retardation (MR) and the stability of clinical features over time.

METHOD: A purpose-designed assessment protocol was developed based on best-practice recommendations in the research literature. Diagnostic reliability, investigated in a group of 20 children with MR, was found to be very good (kappa = 0.87). Using this protocol, the clinical service identified 10 children with an initial diagnosis of schizophrenia. This group was then reassessed 2 years later.

RESULTS

At the end of 2 years, 8 of the 10 children with schizophrenia still warranted this diagnosis. However, there was considerable instability in relation to certain diagnostic criteria, notably delusions and visual hallucinations. In all cases some improvements in severity were seen at follow-up. However, the eight whose schizophrenia was confirmed at follow-up showed major deterioration in cognitive level.

CONCLUSIONS

It is possible to make reliable diagnoses of early-onset schizophrenia in people with MR, provided the assessment system is carefully structured and pays attention to all the important sources of information. However, symptoms should be reviewed frequently, particularly those that cannot be substantiated by patient interview.