ABSTRACT
Objective To explore the relationship between cognitive function and oxidative stress biochemical markers in patients with bipolar disorder. Methods One hundred forty-six patients who met the DSM-Ⅳ bipolar disorder diagnostic criteria including 83 patients with stable phase,42 patients with manic episodes and 21 patients with depression and 115 normal controls were recruited. Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to assess cognitive function. Biochemical indicators were measured including superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT), malonaldehyde (MDA), total antioxidant capacity (T-AOC) and nitric oxide (NO). Results The immediate memory, speech function, attention, time-delay memory, and total score of patients in biphasic stable phase, manic phase, and depression were lower than those in the control group (P<0.01). The visual breadth scores of patients in manic and depression were lower than those in the control group (P<0.01), and the attention scores and total scores were lower than those in the stable group (P<0.01). The delayed memory score of patients with depression was lower than that of stable group (P=0.04). The MDA level of patients with manic episode and depression was higher than that of stable group (P<0.01); the level of NO in manic, depression and control group was higher than that in stable group, and CAT level was low in the stable phase group (P<0.05). In the stable phase group, the visual breadth (r=-0.50, P=0.04), attention (r=-0.67, P<0.01), delayed memory (r=-0.61, P=0.01) were correlated with GSH-PX respectively; time-delay memory was negatively correlated with T-AOC (r=-0.54, P=0.03). The speech function of the biphasic mania phase group was negatively correlated with SOD (r=-0.46, P=0.01). The immediate memory of the biphasic depression group was positively correlated with NO (r=0.61, P=0.02); delayed memory was positively correlated with CAT (r=0.67, P=0.01); speech function (r=-0.76, P<0.01) and cognitive total score (r=-0.59, P=0.03) were negatively correlated with GSH-PX. Conclusion Patients with bipolar disorder have varying degrees of cognitive decline and oxidative stress changes, and some antioxidant enzyme systems are associated with cognitive function.