Attention deficits assessed by Continuous Performance Test and Span of Apprehension Test in Japanese schizophrenic patients

To examine whether attention deficits in the Continuous Performance Test (CPT) and in the Span of Apprehension Test (SPAN) are observed in Japanese schizophrenics, 49 chronic medicated schizophrenics and 43 normal controls were administered the UCLA version of CPT and SPAN. To investigate whether each measure of the CPT and the SPAN is independently correlated to symptoms, a hierarchical multiple regression was conducted with the attentional measures and age as independent variables and with the conceptual disorganization scores on the Brief Psychiatric Rating Scale (BPRS) as a dependent variable in schizophrenic subjects. Decreased performance on the CPT and SPAN measures was observed in the Japanese patients. This indicates that the CPT and the SPAN can detect the attention deficits of schizophrenics in Japan as well as Europe and the US. The SPAN scores in the present study were lower than in previous studies. This may be due to a lower level of familiarity of Japanese subjects with the Roman alphabet. Each measure of the CPT and the SPAN was significantly correlated with the conceptual disorganization scores after controlling for the other measure and age. We concluded that each deficit in sustained attention and processing capacity was independently related to formal thought disorder in schizophrenia.