Lithium, which is often used to treat bipolar disorder, can cause acquired diabetes insipidus (characterized by the excretion of large volumes of dilute urine) by decreasing the expression of the aquaporin 2 gene.

Cerebrospinal fluid analysis to exclude infections such as tertiary syphilis or subacute sclerosing panencephalitis is recommended. Toxicity from bismuth, bromides, and lithium must be ruled-out. Myoclonus is usually more prominent early in toxic/metabolic disorders than in Creutzfeldt-Jakob disease, and seizures in CJD are usually late ¹⁾