Hi I understand your concern. How it can possible to diagnose polydypsia in schizophrenia. It is only excessive drinking of water due to disorganized behavior. Due to excess water there is dilution hyponitremia. It is necessary to give less sodium supplement other wise due to diuresis electrolyte imbalance occur. Please consult nephrologist to get best help. Restrict water intake is the best key to treat it. Propel can be given. Still have a query then feel free to ask. Thank you.