I am not sure if Lithium affected my cycles or not. I only started it when I had just had a baby so my cycles were already weird. I used to have cycles every 28 days like clockwork and they were HEAVY. I would pass out from pain and had awful PMS that made me so labile... But pregnancy/birth made my cycles much lighter in general.

The lithium side effects really reduce my quality of life but bipolar sucks too. Gah!