Lithium has many adverse effects limiting its prescription. Creatine kinase (CK) is released when skeletal muscle cells are damaged. Psychiatric patients with remarkable CK elevations commonly indicate to two life-threatening physical conditions, rhabdomyolysis and neuroleptic malignant syndrome (NMS). Lithium use is related to rhabdomyolysis and NMS, but the association of lithium and asymptomatic CK elevation had not been reported.