Plasma levels of leptin and adiponectin and depressive symptoms in young adults

Circulating levels of adipokines are known to be associated with depression. This study aimed to investigate a possible association between leptin, adiponectin and dimensional measures of depressive symptoms in young adults with and without psychiatric illness. Total plasma adiponectin and leptin levels were measured in 194 young adults seeking psychiatric ambulatory care and 57 healthy controls. Depressive symptoms were assessed using the Montgomery-Asberg Depression Self-Rating Scale (MADRS-S). Analysis was performed on men and women separately. P-leptin levels were significantly elevated in patients compared with controls and correlated with total MADRS-S scores in the women. Women with P-leptin in the highest quartile reached a significantly higher MADRS-S score than women in the lowest quartile, but this difference disappeared after adjusting for body mass index (BMI) and antidepressant use. MADRS-S score was associated with P-leptin in female patients without antidepressant use, independently of BMI. There was no association between P-leptin levels and current major depression. P-adiponectin levels were not associated with depressive symptoms or current major depression. The findings indicate that P-leptin levels are associated with depressive symptom severity in young women; however, the association is linked to other factors, which challenges its usefulness as a biomarker for depression in clinical psychiatry.