Decreased Levels of Fasting Serum Leptin in Patients With Schizophrenia: A Case-Control Study

Objective: Evidence suggested that leptin may be implicated in the pathophysiology of metabolic disruptions in schizophrenia. The findings of the leptin in patients with schizophrenia have been inconsistent. The aim of this study was to evaluate fasting leptin in the patients with schizophrenia and the association with leptin levels and gender, BMI, clinical variables such as psychopathology scores, suicidal behaviour and type of medication. Methods: Forty-eight patients with schizophrenia and 36 age-gender-BMI matched healthy controls (HC) were assessed. We collected venous blood samples in the morning and serum leptin were measured using the ELISA kit. Results: The levels of fasting leptin were significantly decreased in patients with schizophrenia compared with the HC (P=0.021), also after adjusting for confounders (P=0.009). In the regression analysis, being female (beta=-0.51, t=-3.458, P<0.001) and higher BMI (beta=3.675, t=3.675, P<0.001) were found significant predictor to higher level of the fasting leptin and we did not observe a relationship between fasting level of leptin and age, smoke status, cumulative antipsychotic use, clinical status and having suicidal attempt in patients with schizophrenia. Conclusion: The exploratory study detected decreased fasting leptin levels and significant relationships between higher leptin levels and gender and BMI in the stable medicated patients with schizophrenia. Future studies are considered the role of adipose tissue related pathways and gender differences to understand the underlying mechanisms of metabolic disruptions in patients with schizophrenia.