Figure 2.

The performance of people with schizophrenia (SZ) and healthy nonpsychiatric comparison subjects (NCS) in the 5-choice continuous performance test (5C-CPT). People with SZ (n=20) exhibited impaired attention compared with NCS (n=23) as measured by a reduced sensitivity index (a). This attentional deficit was unlikely because of changes in bias of responding given the lack of difference in responsivity index between the two groups (b). Reaction times were slower in SZ but not significantly so (c). Poorer attention was driven by a significant reduction in hit rate (d), with only a modest increase in false alarm responses (e). Variability in reaction time was significantly larger in patients with SZ (f). The poorer overall hit rate of SZ subjects was driven by increased misses over time with a decrement in performance occurring earlier and to a greater extent than NCS (g). Although the accuracy of performance was reduced in people with SZ compared with NCS, this difference was not significant (h). Data presented as mean+s.e.m., *P<0.05 when compared with NCS, ^#P<0.05 when compared with trial period 0–80.