title: Serum Brain-derived Neurotrophic Factor Levels among Euthymic Adolescents with Bipolar Disorder Type I.
abstract: BACKGROUND
  Bipolar disorder (BD) has been increasingly associated with abnormalities in neuroplasticity and cellular resilience in brain regions that are involved in mood and that affect regulation. Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family that regulates neuroplasticity. The aims of the current study were to compare serum BDNF levels in euthymic adolescents with BD type I with those in controls and to investigate the relationship between clinical variables and serum BDNF levels in adolescents with BD type I.
  
  
  METHODS
  Twenty-five adolescents diagnosed with BD type I and 17 healthy control subjects within the age range of 15-19 years were recruited. Diagnoses were made by two experienced research clinicians using the Kiddie and Young Adult Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version and the affective module of Washington University in St. Louis Kiddie and Young Adult Schedule for Affective Disorders and Schizophrenia-Present State and Lifetime. Blood samples were taken during euthymia, which was defined as Young Mania Rating Scale and Hamilton Depression Rating Scale scores below 7.
  
  
  RESULTS
  The comparison of BDNF serum levels between the case and healthy control groups revealed no significant differences. In the case group, BDNF levels were significantly lower in patients being currently treated with lithium.
  
  
  CONCLUSIONS
  Similar to normal BDNF levels in adult patients with BD, the normal BDNF serum levels that we found in the euthymic state in adolescents and early adulthood may be related to the developmental brain stage in our study group. It may also show a common neurobiological basis of pediatric and adult BD. Further investigations evaluating BDNF levels in different mood states could help identify the role of BDNF in the underlying pathophysiology of BD.
authors.affiliation: Clinic of Child and Adolescent Psychiatry, Dr. Behçet Uz Pediatrics and Surgery Training and Research Hospital, İzmir, Turkey.
authors.forename: Nagihan
authors.initials: N
authors.lastname: Cevher Binici
authors.affiliation: Department of Child and Adolescent Psychiatry, Dokuz Eylül University School of Medicine, İzmir, Turkey.
authors.forename: Fatma Neslihan
authors.initials: FN
authors.lastname: Inal Emiroğlu
authors.affiliation: Department of Medical Biochemistry, Dokuz Eylül University School of Medicine, İzmir, Turkey.
authors.forename: Halil
authors.initials: H
authors.lastname: Resmi
authors.affiliation: Department of Preventive Oncology, Dokuz Eylül University School of Medicine, İzmir, Turkey.
authors.forename: Hülya
authors.initials: H
authors.lastname: Ellidokuz
keywords: Brain-derived neurotrophic factor; adolescent; bipolar disorder; neurotrophin