It has been repeatedly demonstrated that schizophrenic pa-
tients are impaired in the comprehension of sentences with
complex syntax. We investigated the hypothesis that this
syntactic comprehension impairment in schizophrenia is not a
purely linguistic dysfunction, but rather the re ̄ection of a
cognitive sequence processing impairment that is revealed as
task complexity increases. We tested 10 schizophrenic patients
using a standard measure of syntactic comprehension, and a
non-linguistic sequence processing task, both of which required
simple and complex transformation processing. Patients
performance impairment on the two tasks was highly corre-
lated (r2 0.84), and there was a signi®cant effect for complex-
ity, independent of the task. These results are quite similar to
those of aphasic patients with left hemisphere lesions. This
suggests that syntactic comprehension de®cits in schizophrenia
reveal the dysfunction of cognitive sequence processing
mechanisms that can be expressed both in linguistic and non-
linguistic sequence tasks. NeuroReport 11:2145±2149 & 2000
Lippincott Williams & Wilkins.
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