Why does postpsychotic IQ decline in childhood-onset schizophrenia?
OBJECTIVE
The authors' goal was to examine whether the postpsychotic decline in full scale IQ during adolescence for patients with childhood-onset schizophrenia is due to a dementing process or simply failure to acquire new information and skills.


METHODS
Linear regression was used to determine the rate of change for scaled and raw scores on subtests of 31 patients with childhood-onset schizophrenia. The resulting slopes were examined and related to changes in the patients' brains determined by magnetic resonance imaging.


RESULTS
Three postpsychotic subtest scaled scores declined significantly: picture arrangement, information, and block design. In contrast, there was no decline in the non-age-corrected (raw) scores for any subtest. A significant correlation was found between decrease in hippocampal volume and a smaller increase in raw score on the information subtest.


CONCLUSIONS
The decline during adolescence in the full-scale IQ of patients with childhood-onset schizophrenia does not reflect dementia but, rather, an inability to acquire new information and abilities.
Bedwell
J S
JS
Child Psychiatry Branch, NIMH, Bethesda, MD 20892, USA.
Keller
B
B
Smith
A K
AK
Hamburger
S
S
Kumra
S
S
Rapoport
J L
JL
D000293:Adolescent; D017668:Age of Onset; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007361:Intelligence Tests / Q000706:statistics & numerical data*; D016014:Linear Models; D008297:Male; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index