10% (N = 15) discontinued during the open‐label phase because of AE; weight gain (33%), gastrointestinal discomfort (27%), tremors (20%), dizziness (7%), cognitive difficulties (7%), and polyuria/polydipsia (7%) the most common AE; tremors and polyuria/polydipsia, in both treatment groups. A significant increase in alanine transaminase levels occurred in the Li+ and VPA CT group (+19.60 U/L) compared to the LI + monotherapy group (−30.83 U/L; p = 0.029). The gene discussed is GPT; the disease is Polydipsia.