title: Influence of levothyroxine in augmentation therapy for bipolar depression on central serotonergic function.
abstract: BACKGROUND
  Adjunctive treatment with supraphysiological doses of levothyroxine (L-T4) in bipolar depression shows promise, but the neurobiological mechanisms underlying clinical improvement are unknown. It has been postulated from animal studies that exogenous thyroid hormones may exert their modulatory effects in patients with affective disorders via an increase in serotonergic neurotransmission. Therefore, we investigated the loudness dependence of auditory evoked potentials (LDAEP) as a measure of central serotonergic activity and response to L-T4.
  
  
  METHODS
  This 6-week, double-blind, randomized, placebo-controlled study assessed the efficacy of L-T4 adjunctive to continuing treatment with mood stabilizer and/or antidepressant medication in 20 patients with bipolar depression. LDAEP was assessed before and after treatment with L-T4.
  
  
  RESULTS
  Scores of the Hamilton Depression Rating Scale and Montgomery Asberg Depression Rating Scale decreased significantly during the study. There was no difference in pre- and post-treatment LDAEP between the groups, and no correlation between LDAEP and psychometric measures in the course of the study.
  
  
  CONCLUSIONS
  The hypothesis of a relationship between response of augmentation therapy with levothyroxine in bipolar depression and serotonergic activity could not be confirmed.
authors.affiliation: Department of Psychiatry, Ruhr University Bochum, LWL University Hospital Bochum, Bochum, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Uhl
authors.affiliation: Central Institute of Mental Health, Mannheim, Germany.
authors.forename: J A
authors.initials: JA
authors.lastname: Bez
authors.affiliation: Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Stamm
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Pilhatsch
authors.affiliation: Department of Psychiatry, Ruhr University Bochum, LWL University Hospital Bochum, Bochum, Germany.
authors.forename: H-J
authors.initials: HJ
authors.lastname: Assion
authors.affiliation: Department of Psychiatry, Ruhr University Bochum, LWL University Hospital Bochum, Bochum, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Norra
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Lewitzka
authors.affiliation: Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Schlagenhauf
authors.affiliation: Department of Psychiatry, Ruhr University Bochum, LWL University Hospital Bochum, Bochum, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bauer
authors.affiliation: Department of Psychiatry, Ruhr University Bochum, LWL University Hospital Bochum, Bochum, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Juckel
mesh_terms: D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy* / Q000503:physiopathology* / Q000523:psychology; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D006801:Humans; D008144:Loudness Perception; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012701:Serotonin / Q000502:physiology*; D013974:Thyroxine / Q000494:pharmacology* / Q000627:therapeutic use*
chemical_list: D000928:Antidepressive Agents; D012701:Serotonin; D013974:Thyroxine