Objective To study the expression of endocannabinoid mRNA in the blood of untreated patients with first-episode major depressive disorder,to explore the relationship between the endocannabinoid system and major depressive disorder.Methods Thirty-nine untreated first-episode major depressive disorder patients diagnosed with DSM-Ⅳ and 35 healthy volunteers were included and assessed with the Wisconsin Card Sorting Test and the Stroop Color Word Test.Their blood was collected in the fasting state and analyzed to test the possible differences of mRNA expression of cannabinoid receptor 1 (CB1) and fatty acid amide hydrolase (FAAH) between depressive subjects and healthy controls.The patients' severity of symptoms was assessed with HAMD17.Results (1) Compared with controls (0.24 ± 0.26),there was significantly lower levels of CB1 receptor mRNA in the blood of patients with major depressive disorder (0.13-± 0.22;Z =-1.965,P ＜ 0.05);the levels of CB1 receptor mRNA exhibited a significant correlation with weight factor score of the HAMD17 (r =0.484,P =0.001).(2)There was no difference between the expression of FAAH mRNA(0.16 ± 0.24) and controls (0.17 ± 0.24;Z =-1.413,P ＞ 0.05);Levels of FAAH mRNA exhibited a significant correlation with patients' cognition factor score of HAMD17 (r =0.345,P =0.045).Conclusions The lower endocannabinoid mRNA expression in the blood of patients with depression may be involved in the pathogenesis of major depression.

Objective To study the expression of endocannabinoid mRNA in the blood of untreated patients with first-episode major depressive disorder,to explore the relationship between the endocannabinoid system and major depressive disorder.Methods Thirty-nine untreated first-episode major depressive disorder patients diagnosed with DSM-Ⅳ and 35 healthy volunteers were included and assessed with the Wisconsin Card Sorting Test and the Stroop Color Word Test.Their blood was collected in the fasting state and analyzed to test the possible differences of mRNA expression of cannabinoid receptor 1 (CB1) and fatty acid amide hydrolase (FAAH) between depressive subjects and healthy controls.The patients' severity of symptoms was assessed with HAMD17.Results (1) Compared with controls (0.24 ± 0.26),there was significantly lower levels of CB1 receptor mRNA in the blood of patients with major depressive disorder (0.13-± 0.22;Z =-1.965,P ＜ 0.05);the levels of CB1 receptor mRNA exhibited a significant correlation with weight factor score of the HAMD17 (r =0.484,P =0.001).(2)There was no difference between the expression of FAAH mRNA(0.16 ± 0.24) and controls (0.17 ± 0.24;Z =-1.413,P ＞ 0.05);Levels of FAAH mRNA exhibited a significant correlation with patients' cognition factor score of HAMD17 (r =0.345,P =0.045).Conclusions The lower endocannabinoid mRNA expression in the blood of patients with depression may be involved in the pathogenesis of major depression.