Lithium therapy is cornerstone in therapy of bipolar disorders. A well known side-effect of lithium therapy is a urinary concentration defect which manifests in it's most severe form as nephrogenic diabetes insipidus. The development of urinary concentration defects and its progression to nephrogenic diabetes insipidus in the population of lithium treated patients is unknown and therefore this study aims to evaluate the decline of urinary concentration defects in a Dutch population of lithium treated patients. In this prospective cohort study, 51 participants treated with lithium at Canisius Wilhelmina Hospital, Nijmegen and included in the previous study in 2012 will be approached to undergo a follow-up dDAVP-test.

Inclusion Criteria:

• included in the previous study
• men and women
• age ≥ 18 years

Exclusion Criteria:

• General contra-indications for participation in a trial:

  • inability to give informed consent
  • pregnancy
  • unstable psychiatric condition

• Alternative causes of (nephrogenic) diabetes insipidus:

  • hypokalemia (plasma potassium < 3.0 mmol/l)
  • severe hypercalcemia (albumin-corrected plasma calcium > 2.80 mmol/l)
  • hyperglycemia (plasma glucose > 10.0 mmol/l)
  • history of amyloidosis, Sjögren's syndrome or Sickle cell anemia
  • previous treatment with ifosfamide
  • established primary polydipsia or central diabetes insipidus

• Contra-indications for dDAVP administration:

  • inability to comply with water restriction
  • renal insufficiency (GFR < 45 ml/min/1.73 m2)
  • hyponatremia (plasma sodium < 130 mmol/l)
  • instable angina pectoris
  • decompensated cardial insufficiency

• Other:

  • concomitant treatment with desmopressin or democlocycline

The 51 patients treated with lithium who were included in the previous study in 2012/2013, in which they were subject to a dDAVP test.