Neuropsychological deficits in pediatric patients with childhood-onset schizophrenia and psychotic disorder not otherwise specified

Objective: Children with transient psychotic symptoms and serious emotional disturbances who do not meet current criteria for schizophrenia or other presently recognized diagnostic categories commonly present diagnostic and treatment problems. Clarifying the connections between children with narrowly defined schizophrenia and children with a more broadly defined phenotype (i.e., Psychotic Disorder Not Otherwise Specified, PD-NOS) has implications for understanding the pathophysiology of schizophrenia. In this study, the neuropsychological test performance of a subgroup of children with atypical psychosis was compared with that of patients with childhood-onset schizophrenia (COS). Method: Cognitive function was assessed with neuropsychological test battery regimens in 51 neuroleptic-nonresponsive patients within the first 2 weeks after admission while receiving stable medication. Only those patients who had an IQ > 70 at NIMH testing (24 PD-NOS, 27 COS) were included in this analysis. Seventeen (39%) of 44 COS subjects were unavailable for this study as their IQ tested < 70. The PD-NOS patients were younger than the COS patients at the time of testing (12.0 +/- 2.8 vs 14.4 +/- 1.8 years, respectively, p < 0.004). The test levels of these groups were compared with each other. Results: The neuropsychological test results for the PD-NOS and COS patients were 1-2 standard deviations below normative data across a broad array of cognitive functions. There were no overall differences in the test levels for the six summary scales (F = 2.82, df = 1, 36, p = 0.10) or in the profile shape (F = 1.70, df = 5, 180, p = 0.14) between the PD-NOS and COS groups. For the COS patients, there was a significant difference between their mean full-scale WISC IQ (84.7 +/- 16.2) and their average standard scores for both the spelling (97.7 +/- 16.1, n = 23, t = 4.0, p = 0.001) and reading decoding subtests (97.7 +/- 13.7, n = 23, t = 3.7, p = 0.001) of the Kaufman Test of Educational Achievement. Conclusions: Treatment-refractory PD-NOS and COS patients share a similar pattern of generalized cognitive deficits, including deficits in attention, learning and abstraction which are commonly observed in adult patients with schizophrenia. These data support a hypothesis that at: least some of the PD-NOS cases belong within the schizophrenic spectrum, which is of importance for future genetic studies planned for this cohort. (C) 2000 Elsevier Science B.V. All rights reserved.