title: Starting lithium prophylaxis early v. late in bipolar disorder.
abstract: BACKGROUND
  No study has investigated when preventive treatment with lithium should be initiated in bipolar disorder.
  
  
  OBJECTIVE
  To compare response rates among patients with bipolar disorder starting treatment with lithium early v. late.
  
  
  METHODS
  Nationwide registers were used to identify all patients with a diagnosis of bipolar disorder in psychiatric hospital settings who were prescribed lithium during the period 1995-2012 in Denmark (n = 4714). Lithium responders were defined as patients who, following a stabilisation lithium start-up period of 6 months, continued lithium monotherapy without being admitted to hospital. Early v. late intervention was defined in two ways: (a) start of lithium following first contact; and (b) start of lithium following a diagnosis of a single manic/mixed episode.
  
  
  RESULTS
  Regardless of the definition used, patients who started lithium early had significantly decreased rates of non-response to lithium compared with the rate for patients starting lithium later (adjusted analyses: first v. later contact: P<0.0001; hazard ratio (HR) = 0.87, 95% CI 0.76-0.91; single manic/mixed episode v. bipolar disorder: P<0.0001; HR = 0.75, 95% CI 0.67-0.84).
  
  
  CONCLUSIONS
  Starting lithium treatment early following first psychiatric contact or a single manic/mixed episode is associated with increased probability of lithium response.
authors.affiliation: Lars Vedel Kessing, MD, DMSc, Psychiatric Center Copenhagen, Department O, and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Eleni Vradi, MSc, Per Kragh Andersen, MSc, PhD, DMSc, Department of Biostatistics, University of Copenhagen, Denmark.
authors.forename: Lars Vedel
authors.initials: LV
authors.lastname: Kessing
authors.affiliation: Lars Vedel Kessing, MD, DMSc, Psychiatric Center Copenhagen, Department O, and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Eleni Vradi, MSc, Per Kragh Andersen, MSc, PhD, DMSc, Department of Biostatistics, University of Copenhagen, Denmark.
authors.forename: Eleni
authors.initials: E
authors.lastname: Vradi
authors.affiliation: Lars Vedel Kessing, MD, DMSc, Psychiatric Center Copenhagen, Department O, and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Eleni Vradi, MSc, Per Kragh Andersen, MSc, PhD, DMSc, Department of Biostatistics, University of Copenhagen, Denmark.
authors.forename: Per Kragh
authors.initials: PK
authors.lastname: Andersen
mesh_terms: D000328:Adult; D018692:Antimanic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000175:diagnosis / Q000188:drug therapy*; D003718:Denmark; D005260:Female; D006801:Humans; D008094:Lithium / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012042:Registries; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018692:Antimanic Agents; D008094:Lithium