Müsemma Karabel - Associate Professor of Pediatrics, Dicle University, School of Medicine, Department of Adolescent Unit, Diyarbakır, Turkey.
Şeref Şimşek - Assistant Professor of Pediatrics, Dicle University, School of Medicine, Department of Child Psychiatry, Diyarbakır, Turkey.
Yusuf Kenan Haspolat - Professor of Pediatrics, Dicle Üniversity, Medicine School, Director of Pediatric Endocrinology and Adolescent Unit, Diyarbakır, Turkey.
Selvi Kelekçi - Associate Professor of Pediatrics, Dicle University, School of Medicine, Department of Pediatrics, Diyarbakır, Turkey.

Background Depression, a challenging disorder, affects 1–6% of adolescents and early onset often predicts more serious manifestations in later life. Elevated Parathyroid hormone (PTH), parathormone levels have reported among adults with depression. In this study, the roles of 25(OH) D (vitamin D) and parathormone during adolescence, in which the frequency of depression is high, were studied. Materials and Methods Patients who were followed-up jointly at both clinics and whose 25(OH) D and PTH levels were evaluated and questioned Depression Scale for Children for depression at the same time, were included in the study. Cases’ socio-demographic data, 25(OH) D and PTH levels and Depression Scale’ scores were recorded. Results Depression was diagnosed in 35 (25.3%) of the 138 patients. No differences were found between vitamin D and parathormone in terms of age and gender in groups either with or without depression. Negative correlation was found between the vitamin D levels and depression score in the group with depression   (r=-0.368; P=0.03). A significant and positive correlation was found between the PTH levels and depression score (r=0.399; P=0.018). A significant and negative correlation was found between 25(OH) D and PTH levels. Conclusion Even if clinical depression is absent, the frequency of depressive symptoms is increased with decreased vitamin D levels and increased PTH levels, independent of other factors.  The prevention of depression, specifically in adolescents, is important to decrease possible suicidal and homicidal thoughts that might arise during adulthood, and substance abuse. Maintaining vitamin D support during adolescence, as with the first year of life, is necessary for both the prevention and treatment of depression.

Adolescent, Depression, Parathyroid hormone, Prevention, Vitamin D