Thought disorder in attention-deficit hyperactivity disorder

OBJECTIVE: This study compared thought disorder and associated cognitive variables in attention-deficit hyperactivity disorder (ADHD) and schizophrenia. METHOD: Speech samples of 115 ADHD, 88 schizophrenic, and 190 normal children, aged 8 to 15 years, were coded for thought disorder. A structured psychiatric interview, the WISC-R, the Continuous Performance Test, and the Span of Apprehension task were administered to each child. RESULTS: The ADHD and schizophrenic groups had thought disorder compared with the normal children. However, the subjects with ADHD had a narrower range of less severe thought disorder than did the schizophrenic subjects. The younger children with ADHD and schizophrenia had significantly more thought disorder than did the older children with these diagnoses. IQ, attention, and working memory were associated with thought disorder in the ADHD but not the schizophrenic group. CONCLUSIONS: Thought disorder in childhood is not specific to schizophrenia and reflects impaired development of children's communication skills.