The most common urological side effects of lithium include polyuria and polydipsia.[15] Previous studies have reported that lithium can cause nephrogenic diabetes insipidus, which may be linked to reduced kidney sensitivity to vasopressin[19] and impaired expression of aquaporin-2 in the collecting duct principal cells,[20] leading to impaired water reabsorption. Here, AQP2 is linked to Polydipsia.