To investigate the correlation between plasma neuropeptide tyrosine (NPY) and substance P (SP) levels and anxiety and depression in patients with functional dyspepsia (FD).

Anxiety and depression scores of 30 patients with FD and 30 healthy volunteers were obtained by self-rating anxiety scale (SAS) and self-rating depression scale (SDS). The peripheral blood of participants was collected and the enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of plasma NPY and SP.

The levels of NPY and SP were (94.82±18.53)ng/L and (35.16±8.42)ng/L in the FD group respectively, and were (118.53±22.29)ng/L and (47.65±11.06)ng/L in the healthy controls respectively, the differences were statistically significant (t=8.13, 7.04; P<0.01). SAS and SDS scores were (67.4±14.2) and (63.9±13.5) in the FD group respectively, and were (44.6±11.7) and (41.1±10.6) in the healthy controls respectively, the differences were statistically significant (t=12.44, 11.18; P<0.01). There were no significant differences in gender, age and disease duration between FD patients and FD patients with anxiety and depression(χ²=1.22, 0.56, 2.14; P>0.05). The plasma NPY levels in FD patients were negatively correlated with SAS and SDS scores (r=-0.70, -0.61; P<0.001). The plasma SP levels in FD patients were negatively correlated with SAS and SDS scores (r=-0.74, -0.56; P<0.01).

The levels of plasma NPY and SP in FD patients are reduced, and negatively correlated with anxiety and depression scores. SP and NPY may be involved in the pathogenesis of functional dyspepsia with anxiety and depression.