Journal of International Psychiatry

Objective: To compare differences of the serum levels of neuropeptide Y (NPY) and substance P (SP) between patients with unipolar depression and bipolar depression, and then explore the potential linkage between NPY/SP and the severity of depression.Method: We recruited 39 unipolar depressive patients, 38 bipolar depressive patients and 40 well-matched healthy controls（HC） in this study. The diagnoses were made according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. The serum NPY and SP concentrations were determined by enzyme-linked immunosorbent assay. The Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA) were applied to assess the severity of clinical symptoms of depression and anxiety. Results ：The serum NPY levels in both unipolar and bipolar depression group were lower than HC group [(5.87±4.16) μg/mL, μg/mL (6.21±2.35) V.S (8.36±3.32) μg/mL, P=0.04], while the serum levels of SP in two group were significantly higher than HC group [(6.19±2.57 ) μg/mL, μg/mL (5.63±2.51) V.S (4.26±1.14) μg/mL, P=0.04, 0.03], the Post-Hoc comparison found that serum SP levels in unipolar depression were higher than bipolar depression group (P=0.03), but there was no significant difference of serum NPY levels between two groups. Correlation analysis detected that the NPY level was negatively correlated with HAMD scores in unipolar depression group (r=-0.61, P=0.04).Conclusion： The NPY and SP maybe involve in the pathophysiology of depression, and the NPY and SP would be useful biomarkers to separate the subtype of depression and evaluate the severity of disease.

Unipolar depressive disorder; Bipolar depressive disorder; Neuropeptide Y; Substance P; Correlation analysis.