Abstract: Objective To compare the cognitive functions between patients with treatment-resistant depression and first-episode depression. Methods A total of 80 major depressive disorder patients admitted in our hospital from March 2015 to December 2016 were included in this study. The patients were divided into treatment-resistant depression group (n= 40) and first-episode depression group (n=40). Another 40 healthy individuals were used as the control group. The basic data of patients were collected, and Hamilton depression scale (HAMD)- 17 was used to assess the severity of the disease. The performing functions were assessed by trail marking test and stroop color-word test. The attention functions were assessed by digital span test. Memory functions were assessed by Hopkins verbal learning test revise (HVLT-R). After treatment for 6 months, cognitive functions were assessed again in first-episode depression group. Results Compared with control group， the scores of trail marking test (TMT) increased, while the scores of digital span test, stroop color-word test, stroop color colorword test, HVLT-R reduced in treatment-resistant depression group and first-episode depression group (P < 0.05). The scores of TMT, HAMD-17 were lower in first-episode depression group than those of treatment-resistant depression group (P < 0.05). There were no significant differences in other indexes between groups. After six months treatment, the trail marking test score and HAMD-17 reduced, but digital span test, stroop color-word test increased in first-episode depression group (P < 0.05). Conclusion The cognitive function damages severely in patients with treatment-resistant depression and first-episode depression, but there is no obvious difference in severity between two groups of patients.

Key words: depressive disorder, cognition, treatment-resistant depression, first-episode depression, HAMD-17