Comparison of Cognitive Controls in Patients with Bipolar I Disorder and Their Unaffected First-Degree Relatives

OBJECTIVES: This study intended to identify the deficits of cognitive control among patients with bipolar I disorder and their first-degree relatives, and identify the possibility of cognitive control as an endophenotype of bipolar disorder. METHODS: The study included three groups: euthymic states patients with bipolar I disorder (n = 55), unaffected first-degree relatives of probands with bipolar I disorder (n = 30), and a healthy control group (n = 51), that was matched on age, sex, and years of education. The AX version of the continuous performance test (CPT) was used to examine cognitive control. Error rate, correct response times of each subsets (AX, BX, AY, BY), and d' as an indication of accuracy sensitivity index were calculated. Psychopathology, intelligence, and psychomotor speed were also assessed. RESULTS: Patients with bipolar I disorder showed significantly worse error rates in the AX (p = 0.01) and BX (p = 0.02) subsets and d' (p = 0.05) than the others. They also showed more delayed correct response times than the healthy control group and first-degree relatives in all subsets (p < 0.01). But first-degree relatives showed neither high error rates nor delayed correct response times than healthy control group. CONCLUSIONS: These findings suggest that cognitive control is impaired in bipolar I disorder but less likely to be an endophynotype of bipolar I disorder.

Comparison of Cognitive Control Deficits in Patients with Schizophrenia and Their Unaffected First-Degree Relatives / 신경정신의학

OBJECTIVES: This study aimed to identify the differences in the profiles of cognitive control deficits among schizophrenic patients and endophenotypes. METHODS: The study examined three groups: remitted patients with schizophrenia (n=54), unaffected first-degree relatives of the probands with schizophrenia (n=36), and a healthy control group (n=51), which were all matched for age, sex, and years of education. The AX version of the continuous performance test was used to examine cognitive control. The error rate, correct response times of each subset (AX, BX, AY, BY), and d′ as an indication of the accuracy sensitivity index were calculated. The psychopathology, intelligence, and psychomotor speed were also assessed. RESULTS: Patients with schizophrenia showed significantly poorer error rates and d′ in the AX and BX subsets than the others. They showed more delayed correct response times than the healthy control group in all subsets. The first-degree relatives also showed more delayed correct response times in the BX and AY subsets than the healthy control group, but were similar to the patients. CONCLUSION: These findings suggest that cognitive control is impaired in schizophrenia and endophynotypes possibly share this delayed information processing from the higher loading states of cognitive control.