Involvement of the alpha2-adrenergic system in polydipsia in schizophrenic patients: a pilot study

Psychopharmacology (Berl). 1997 Apr;130(4):382-6. doi: 10.1007/s002130050254.


Animal studies have suggested the involvement of the adrenergic system in drinking behavior. The present study investigated the involvement of the alpha2-adrenergic system in the polydipsia of patients with chronic schizophrenia by use of an alpha2 agonist and an antagonist. Four patients with schizophrenic disorders accompanied by intermittent hyponatremia and polydipsia were the subjects of, and completed, this study. Drinking behavior was assessed by calculating the percent of maximum weight gain [PMWG: (maximum diurnal weight - standard weight) x 100/standard weight]. Standard weight was defined as body weight after 8 h of water restriction. Clonidine (75, 150, and 225 mg/day) increased the PMWG in a dose-dependent manner in the four subjects. In contrast, in three of the subjects, mianserin (30, 60, and 90 mg/day) decreased PMWG, and the severe polydipsia disappeared almost completely. These findings indicate clearly that the alpha2-adrenergic system is involved in the drinking behavior of schizophrenic patients. Mianserin appears to be clinically useful in treating such patients with polydipsia.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adrenergic alpha-Agonists / therapeutic use
  • Adrenergic alpha-Antagonists / therapeutic use*
  • Clonidine / therapeutic use
  • Drinking Behavior / drug effects*
  • Female
  • Humans
  • Male
  • Mianserin / therapeutic use*
  • Middle Aged
  • Receptors, Adrenergic, alpha-2 / drug effects
  • Receptors, Adrenergic, alpha-2 / physiology*
  • Schizophrenia / complications
  • Schizophrenia / drug therapy*
  • Schizophrenia / physiopathology
  • Water Intoxication / etiology
  • Water Intoxication / physiopathology
  • Water Intoxication / prevention & control*


  • Adrenergic alpha-Agonists
  • Adrenergic alpha-Antagonists
  • Receptors, Adrenergic, alpha-2
  • Mianserin
  • Clonidine