Abstract
Objective: Leptin may be involved in the pathophysiology of metabolic disruptions in schizophrenia. The findings of the leptin level in patients with schizophrenia have been inconclusive. The aim of this study was to evaluate fasting leptin levels in the stable patients with schizophrenia and the relationship between 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. After 12 h of fasting, venous blood samples were collected in the morning and serum leptin concentrations were measured using the enzyme-linked immunosorbent assay.

Results: Fasting leptin levels were significantly decreased in patients with schizophrenia compared with the HC (P=0.021), also after controlling for age, gender, and body mass index (BMI) (P=0.009). In the regression analysis, being female (ß=−0.51, t=-3.458, p<0.001) and higher BMI (ß=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 associations 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.

Key words: Leptin, Schizophrenia, Adiposity, BMI, Gender