title: Increased psychiatric morbidity before and after the diagnosis of hypothyroidism: a nationwide register study.
abstract: BACKGROUND
  Thyroid hormones are necessary for fetal brain development, and hypothyroidism in adults has been associated with mood symptoms and reduced quality of life. Nevertheless, our knowledge regarding the association and temporal relation between hypothyroidism and mental disorders is ambiguous. Our objective was to investigate, at a nationwide level, whether a diagnosis of hypothyroidism is associated with psychiatric morbidity.
  
  
  METHODS
  This is an observational cohort study. On the basis of record linkage between different Danish health registers, 2822 hypothyroid singletons each matched with 4 nonhypothyroid controls were identified and followed over a mean period of 6 years (range 1-13). Additionally, we included 385 same-sex twin pairs discordant for hypothyroidism. Diagnoses of psychiatric disorders as well as treatment with antidepressants, antipsychotics, and anxiolytics were recorded. Logistic and cox regression models were used to assess the risk of psychiatric morbidity before and after the diagnosis of hypothyroidism, respectively.
  
  
  RESULTS
  Before the diagnosis of hypothyroidism, such individuals had an increased prevalence of diagnoses with psychiatric disorders (odds ratio, OR, 1.51; 95% confidence interval [CI 1.12-2.04]) and increased prevalence of treatment with antipsychotics (OR 1.49 [CI 1.29-1.73]), antidepressants (OR 1.50 [CI 1.35-1.67]), and anxiolytics (OR 1.28 [CI 1.16-1.41]). After the diagnosis of hypothyroidism, patients had a higher risk of being diagnosed with a psychiatric disorder (hazard ratio, HR, 2.40 [CI 1.81-3.18]), and an increased risk of being treated with antidepressants (HR 1.30 [CI 1.15-1.47]) and anxiolytics (HR 1.27 [CI 1.10-1.47]), but not antipsychotics (HR 1.13 [CI 0.91-1.41]). On the basis of the twin data, we could not demonstrate genetic confounding.
  
  
  CONCLUSIONS
  Subjects with hypothyroidism have an increased risk of being diagnosed with a psychiatric disorder as well as being treated with antidepressants, antipsychotics, and anxiolytics both before and after the diagnosis of hypothyroidism.
authors.affiliation: 1 Department of Endocrinology and Metabolism, Odense University Hospital , Odense, Denmark .
authors.forename: Marianne
authors.initials: M
authors.lastname: Thvilum
authors.forename: Frans
authors.initials: F
authors.lastname: Brandt
authors.forename: Dorthe
authors.initials: D
authors.lastname: Almind
authors.forename: Kaare
authors.initials: K
authors.lastname: Christensen
authors.forename: Thomas Heiberg
authors.initials: TH
authors.lastname: Brix
authors.forename: Laszlo
authors.initials: L
authors.lastname: Hegedüs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014151:Anti-Anxiety Agents / Q000627:therapeutic use; D000928:Antidepressive Agents / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000627:therapeutic use; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D011307:Drug Prescriptions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology* / Q000523:psychology; D038801:International Classification of Diseases; D008297:Male; D008498:Medical Record Linkage; D001523:Mental Disorders / Q000188:drug therapy / Q000453:epidemiology*; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D012042:Registries; D012306:Risk; D055815:Young Adult
chemical_list: D014151:Anti-Anxiety Agents; D000928:Antidepressive Agents; D014150:Antipsychotic Agents