Plasma prolidase levels are high in schizophrenia but not in first-episode psychosis

Assessing the relationship between antipsychotic drug use and prolidase enzyme activity and oxidative stress in schizophrenia patients: a case-control study

BACKGROUND

The relationship between proline, its association with oxidative stress, and its connection to schizophrenia is a subject that has not been sufficiently investigated.

OBJECTIVE

The aim of this study is to evaluate the possible effects of atypical and combined (typical and atypical) antipsychotic use on serum prolidase enzyme activity (SPEA) and serum oxidative stress parameters, and to assess the relationship between SPEA and oxidative stress in patients with schizophrenia.

METHODS

A total of 57 patients with schizophrenia, of which 34 were using atypical (AAPG) and 23 were using combined (typical and atypical) (CAPG) antipsychotic therapy, and 28 healthy volunteers (control group) were included in this case-control study.

RESULTS

SPEA levels of AAPG and CAPG were significantly lower than that of control group ( P  = 0.003). The oxidative stress index (OSI) value of AAPG was significantly higher than the other two groups ( P  = 0.001). SPEA (<1860 U/l) and OSI (≥0.54) could discriminate schizophrenia patients with antipsychotic therapy from control groups ( P  = 0.001 and P  = 0.007, respectively). Lower SPEA levels were associated with antipsychotic use ( P  = 0.007).

CONCLUSION

The SPEA values of patients with schizophrenia on antipsychotics were significantly lower compared to controls. OSI values were significantly higher in atypical antipsychotic recipients compared to those on combined antipsychotics and healthy controls.

Clinical Utility of Fluid Biomarker in Depressive Disorder

Major depressive disorders are ranked as the single largest contributor to non-fatal health loss and biomarkers could largely improve our routine clinical activity by predicting disease course and guiding treatment. However there is still a dearth of valid biomarkers in the field of psychiatry. The initial assumption that a single biomarker can capture the myriad of complex processes proved to be naive. The purpose of this paper is to critically review the field and to illustrate the possible practical application for routine clinical care. Biomarkers derived from DNA analysis are the ones that have received the most attention. Other potential candidates include circulating transcription products, proteins, and inflammatory markers. DNA polygenic risk scores proved to be useful in other fields of medicine and preliminary results suggest that they could be useful both as risk and diagnostic biomarkers also in depression and for the choice of treatment. A number of other possible fluid biomarkers are currently under investigation for diagnosis, outcome prediction, staging, and stratification of interventions, however research is still needed before they can be used for routine clinical care. When available, clinicians may be able to receive a lab report with detailed information about disease risk, outcome prediction, and specific indications about preferred treatments.