I neglected to get my blood tests. My psychiatrist didn't notice because he is a scatter brain. The levels became toxic. I found out by accident getting a blood test for something else. By then the damage was done. My kidneys function at 41% right now. I have chronic kidney disease, stage 3 because of lithium. I take Depakote ER now. It's filtered through the liver. I get blood tests every six months. I'd never take an overdose. I'm not criticizing those who do.