chronic/negative and acute/positive schizophrenia and attention deficits

background: schizophrenia is a psychiatric disorder that impairs several intellectual functions, including attention processes.   objectives: to investigate attention deficit in a group of patients with schizophrenia.   method: thirty patients with schizophrenia hospitalized in three psychiatric wards in shiraz and isfahan and 30 normal healthy subjects matched for age, gender and years of education underwent the following tests:  a computerized continuous performance test (cpt), stroop color-word test and wisconsin card sorting (wcs) test.   results : in the tests performed, patients with schizophrenia preformed poorer than control subjects.  the acute/chronic classification did not predict differences in attention processes among subtypes of schizophrenia, while positive/negative classification predicted differences observed among the patient groups.  the subtypes of schizophrenia (paranoid, undifferentiated and residual) had the same performance in cpt, while they were significantly different in error scores of (wcs) and reaction time in response to stroop stimuli in incongruent color-word condition.   conclusion: the paranoid patients preformed better in contrast to other subtypes on attention related tasks.  the results of the present study suggest that cpt is a valuable test for differentiation of schizophrenia disorder in general, while stroop test and wcs may have better diagnostic value for differentiating subtypes of the disorder.