It really will depend on your own chemistry. Lithium was terrible for me. Caused shaking, tremor, dizziness, and a mental fog that made it impossible to even hold a conversation. I got toxic very easily, on only 900mg. And after all that it didn't help my mood - just made me feel dead.

But as you can see many people here like it. So it is really a gamble. I would just remind you to drink a lot of water and watch how many calories you are drinking. One theory on lithium weight gain is that people are so thirsty all te time that they drink more soda/juice and gain weight that way.