title: Mood-dependent changes of serum lithium concentration in a rapid cycling patient maintained on stable doses of lithium carbonate.
abstract: OBJECTIVE
  Serum lithium levels may be influenced by mood state. We report on a 58-year-old female patient suffering from rapid cycling bipolar disorder. Her serum lithium levels varied greatly, despite stable medication.
  
  
  METHODS
  The patient was observed over a one-year period.
  
  
  RESULTS
  The patient received a stable medication of lithium carbonate (450 mg), valproate (1500 mg), and clozapine (200 mg). Investigating mood and serum lithium levels over one year revealed six manic and six depressive phases. The mean lithium serum level was 0.67 mmol/L in the depressive states, 0.39 mmol/L in the manic states (t = 4.11, p = 0.001 versus depression), and 0.40 mmol/L in the euthymic states (t = 3.58, p = 0.003 versus depression). Noncompliance was ruled out. The patient gained up to 8 kg during manic phases, accompanied by pretibial edema.
  
  
  CONCLUSIONS
  Changes in serum lithium concentration are probably not caused by altered lithium, but by water metabolism. During mania, body water increases, leading to dilution and therefore a reduction in serum lithium levels. As there is no proof for any other known cause of hypervolemia, we propose the hypothesis that the increase in body water is due to a variant of idiopathic edema.
authors.affiliation: Department of Psychiatry 1, Landesnervenklinik Wagner-Jauregg, Linz, Austria. hans.rittmannsberger@gespag.at
authors.forename: Hans
authors.initials: H
authors.lastname: Rittmannsberger
authors.forename: Gertraud
authors.initials: G
authors.lastname: Malsiner-Walli
mesh_terms: D018692:Antimanic Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000097:blood* / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008094:Lithium / Q000097:blood*; D016651:Lithium Carbonate / Q000627:therapeutic use*; D008875:Middle Aged
chemical_list: D018692:Antimanic Agents; D016651:Lithium Carbonate; D008094:Lithium