Premorbid performance IQ deficit in schizophrenia.
OBJECTIVE
Performance IQ (PIQ) is often lower than verbal IQ (VIQ) in schizophrenic patients. Whether PIQ < VIQ precedes psychotic symptoms in schizophrenia remains uncertain.


METHODS
We investigated premorbid IQ scores in 63 subjects assessed at a child and adolescent psychiatric unit (mean age 13.1 years, SD 3.2), who at follow-up in adulthood (mean age 30.9 years, SD 3.9) received a lifetime RDC diagnosis of schizophrenia-related psychosis, affective disorder, or no psychiatric disorder.


RESULTS
Premorbid PIQ < VIQ significantly differentiated the groups with schizophrenia-related psychosis and no psychiatric disorder. Subjects with schizophrenia-related psychosis had a significantly lower mean value for premorbid PIQ, but not VIQ, compared to subjects who developed affective disorder or subjects without psychiatric disorder.


CONCLUSIONS
Our results emphasize premorbid intellectual deficits in schizophrenia. Those deficits might largely be in consequence of an impairment on the PIQ scale.
Amminger
G P
GP
University Hospital for Child and Adolescent Neuropsychiatry, Vienna, Austria.
Schlögelhofer
M
M
Lehner
T
T
Looser Ott
S
S
Friedrich
M H
MH
Aschauer
H N
HN
D000293:Adolescent; D000328:Adult; D002648:Child; D003072:Cognition Disorders / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007360:Intelligence; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D012565:Schizophrenic Psychology; D014705:Verbal Behavior