Psychogenic polydipsia 

excessive thirst and compulsive water drinking.

Signs and symptoms of psychogenic polydipsia include

• Excessive thirst and xerostomia, leading to overconsumption of water
• Hyponatraemia, causing headache, muscular weakness, twitching, confusion, vomiting, irritability etc., although this is only seen in 20–30% of cases.
• Hypervolemia, leading to oedema, hypertension and weight gain in extreme episodes
• Tonic-clonic seizure
• Behavioural changes, including fluid-seeking behaviour; patients have been known to seek fluids from any available source, such as toilets and shower rooms.