[ABSTRACT] Lithium is the most simple drug, from the chemical point of view, among those used in psychiatric therapeutics. Their psychiatric indications are perfectly established. In fact, the Practice Guide of the A.P.A. for the Treatment of Patients with Bipolar Disorder states that the lithium is ?the first election pharmacological treatment for patients with bipolar disorder?, In the same way, provided that the renal and cardiac functions are normal, the lithium salts constitute the election