Electrodermically Nonresponsive Schizophrenia Patients Make More Errors in the Stroop Color Word Test, Indicating Selective Attention Deficit

This study investigated whether skin conductance responsivity is associated with selective attention assessed by the Stroop Color Word Test (SCWT) in schizophrenia patients. The subjects (31 schizophrenia patients and 20 patients with other psychotic diagnoses) were selected from among inpatients of a general hospital psychiatric ward or day hospital attendees. They were matched with 31 healthy volunteers. The patients began experimental sessions immediately after remission of an acute episode. The three groups of participants were subdivided according to electrodermal responsivity into nonresponsive (NR) and responsive (R) groups. After the psychophysiological recording, the SCWT was applied. Results indicated that on the SCWT, the error interference of the NR schizophrenia group was significantly higher than that of all the other groups. Furthermore, the NR schizophrenia patients had significantly more negative symptoms than the R schizophrenia patients. These results suggest that there is a homogeneous subgroup of schizophrenia patients characterized by low neurovegetative responsiveness to external stimuli, predominance of negative symptoms, and selective attention deficit.