title: The effects of levothyroxine replacement or suppressive therapy on health status, mood, and cognition.
abstract: BACKGROUND
  TSH-suppressive doses of levothyroxine (L-T4) have adverse effects on bone and cardiac function, but it is unclear whether central nervous system function is also affected.
  
  
  OBJECTIVE
  The aim of the study was to determine whether women receiving TSH-suppressive L-T4 doses have decrements in health status, mood, or cognitive function.
  
  
  METHODS
  A cross-sectional comparison was made among three groups of women in an academic medical center research clinic.
  
  
  METHODS
  Twenty-four women receiving chronic TSH-suppressive L-T4 doses, 35 women receiving chronic replacement L-T4 doses, and 20 untreated control women participated in the study.
  
  
  METHODS
  Subjects underwent testing at a single outpatient visit.
  
  
  METHODS
  We measured health status (SF-36), mood (Profile of Mood States, Symptom Checklist 90-R, Affective Lability Scale), and cognitive function (declarative memory [Paragraph Recall], working memory [N-back, Subject Ordered Pointing], motor learning [Pursuit Rotor, Motor Sequence Learning Test], and executive function [Letter Cancellation Test, Trail Making Test, Iowa Gambling Test]).
  
  
  RESULTS
  Women receiving TSH-suppressive or replacement L-T4 doses had decrements in health status and mood compared to healthy controls. These decrements were more pronounced in women receiving replacement, rather than suppressive, L-T4 doses. Memory and executive function were not affected in either treated group, compared to healthy controls.
  
  
  CONCLUSIONS
  Women receiving TSH-suppressive doses of L-T4 do not have central nervous system dysfunction due to exogenous subclinical thyrotoxicosis, but TSH-suppressed and L-T4-replaced women have slight decrements in health status and mood that may be related to self-knowledge of the presence of a thyroid condition or other uncharacterized factors. These mood alterations do not impair cognitive function.
authors.affiliation: Division of Endocrinology, Diabetes, and Clinical Nutrition (M.H.S., I.K., A.S., K.G.S.), Division of Biostatistics (D.P.), and Department of Behavioral Neurosciences (J.S.J.), Oregon Health & Science University, Portland, Oregon 97239.
authors.forename: Mary H
authors.initials: MH
authors.lastname: Samuels
authors.forename: Irina
authors.initials: I
authors.lastname: Kolobova
authors.forename: Anne
authors.initials: A
authors.lastname: Smeraglio
authors.forename: Dawn
authors.initials: D
authors.lastname: Peters
authors.forename: Jeri S
authors.initials: JS
authors.lastname: Janowsky
authors.forename: Kathryn G
authors.initials: KG
authors.lastname: Schuff
mesh_terms: D000328:Adult; D000339:Affect / Q000187:drug effects*; D016022:Case-Control Studies; D003071:Cognition / Q000187:drug effects*; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006304:Health Status; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000037:antagonists & inhibitors*; D013974:Thyroxine / Q000008:administration & dosage / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D013972:Thyrotropin; D013974:Thyroxine