WC made a lot of good points.

I'll write the standard and say that what's great for one is not always great for another in terms of mood stabilization and side effects, but having visited bipolar forums for literally 12+ years and having taken both Lithium for several years at doses of 900 to 1200 mg and Lamictal at doses from 100 mg to 300 mg I'll say that Lamictal tends to be a friendlier medication than Lithium for most. Lamictal tends to also be a bit more geared towards depression relief for many compared to Lithium. The question is, what do you need most of? Depression relief, mania relief, or a proper balance? Or other?

My personal experiences with Lithium and Lamictal are this:

Lithium was never my ideal medication. It never did any full job. Though for many it is more of an antimanic, for me it helped more with depression, though never sufficiently. While it is a wonder drug for many (it really can be), for me it equaled 10 side effects total over the course I took it. The only notorious Lithium side effect I didn't experience was weight gain. I was rather slim on Lithium.

Lamictal, for me, has had a proper place in my cocktail in moderation. It is not capable of taming my bipolar 1 mania at all, but it is helpful at curbing and extinguishing much of my depression, with the help of my Seroquel XR. At one point it was a hero ending 1 year of depression that even came back after ECT. However, in my case, 100 mg has always been the max I should take. It can be very activating for me. Some of my worst manias and manias with mixed features resulted from taking too much of it without ample mania preventing medications. Of course for a while at 300 mg with Abilify, I was flying high, but flying too high for me escalates into major danger. But doses of 200 and even much higher are brilliant for many, especially those whose mania is not as likely or easily triggered. It is called a moodstabilizer. For some it is. For me, it's an antidepressant. I don't have any side effects from 100 mg. I did have some mild cognitive impairment at 200 and 300 mg, but it wasn't THAT bad. I did sweat profusely at 300 mg, but I wonder if that was a Lamictal side effect, or hypomania/mania symptom. When I'm hypo/manic, my whole system is on rocket overdrive. Lamictal has always been weight friendly for me.