Oxidative status and prolidase activities in generalized anxiety disorder

Asian J Psychiatr. 2017 Feb;25:118-122. doi: 10.1016/j.ajp.2016.10.008. Epub 2016 Oct 19.


Objective: Prolidase (Pro), an intracellular enzyme necessary for collagen turnover, matrix remodelling and cell growth has been shown to be related to Oxidative Stress (OS). To our knowledge, serum Pro activity in generalized anxiety disorder (GAD) has not been documented yet. In this study, we aimed to evaluate OS and its relation with Pro activity in patients diagnosed with GAD.

Method: Thirty untreated GAD patients and 30 healthy controls were included in the study. Blood samples were collected from all subjects to quantify total oxidant status (TOS), total antioxidant status (TAS) and Pro activity. Oxidative stress index (OSI), the ratio of TOS to TAS, is calculated to evaluate the balance between antioxidants and oxidants. Hamilton Anxiety Rating Scale (HARS) was used to determine the anxiety levels of all subjects.

Results: GAD group demonstrated statistically significantly higher TOS, OSI and Pro levels, when compared with the control group (t=2.947, p=0.005; t=2.874, p=0.006; and t=9.396, p<0.001 respectively). HARS scores were found to be positively correlated with TOS, OSI and Pro levels (p=0.008, r=0.338; p=0.008, r=0.339; and p<0.001, r=0.751 respectively).

Conclusion: The degree of severity of OS is correlated with the levels of Pro. Thus, Pro might be the target enzyme, promising to be a marker for the follow-up of GAD patients. To the best of our knowledge, this study is the first to report a significant relation between Pro activity and GAD.

Keywords: Generalized anxiety disorder; Oxidative stress; Prolidase; Total anxiety disorder; Total oxidant status.

MeSH terms

  • Adult
  • Anxiety Disorders / enzymology*
  • Biomarkers / blood
  • Case-Control Studies
  • Dipeptidases / blood*
  • Female
  • Humans
  • Male
  • Oxidative Stress / physiology*
  • Young Adult


  • Biomarkers
  • Dipeptidases
  • proline dipeptidase