I started taking a low dose of lithium, 450mg every other day, to supplement Wellbutrin which didn't seem to be working well. After one month I had a blood test and my lithium level is <0.1 mmol/L (standard range, 0.6 - 1.2 mmol/L. I am now wondering how low it was before I started taking it, and if that is causing my major depression disorder.