Patients with schizophreniform disorder use verbal descriptions for the representation of visual categories.
BACKGROUND
Neuropsychological impairment is a common finding in schizophrenia. However, a significant proportion of patients are not impaired in conventional neuropsychological tests. In this study, we investigated whether remitted patients with schizophreniform disorder exhibited dysfunctions in specific cognitive tasks.


METHODS
Twenty remitted, highly functioning patients with schizophreniform disorder and 20 control subjects participated in the study. In addition to background neuropsychological evaluation (WAIS-R IQ, Wisconsin Card Sorting Test (WCST), Trail Making B, Rey Osterrieth Complex Figure), subjects received a category learning task. The categories consisted of geometric shapes systematically changing in shape and size. Training included the sequential presentation of category members (visual learning) and verbal description of categories.


RESULTS
The patients with schizophreniform disorder had normal IQ, executive functions/psychomotor speed (WCST and Trail Making B) and visual memory (Rey-Osterrieth Complex Figure). In contrast, they displayed impaired categorization performances after visual learning. The performance of the patients improved markedly after verbal description of categories. Verbal knowledge about categories positively correlated with categorization performance in the patients, but not in the controls.


CONCLUSIONS
Category learning functions, which include decision-making under uncertainty and feature integration, are impaired in patients with schizophreniform disorder who display normal executive functions and visual memory. These patients may use verbal knowledge as a compensatory strategy in visual tasks.
Kéri
S
S
Department of Psychiatry and Physiology, University of Szeged, Szeged, Hungary.
Kelemen
O
O
Benedek
G
G
Janka
Z
Z
D000328:Adult; D010054:Brief Psychiatric Rating Scale; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D009483:Neuropsychological Tests; D011618:Psychotic Disorders / Q000150:complications* / Q000175:diagnosis; D012720:Severity of Illness Index; D014796:Visual Perception