lithium is a naturally occurring salt, & is considered a mood stabilizer, not an antipsychotic (risperdal & abilify r antipsychotics, lamictal is an anticonvulsant, or epilepsy drug, that is also a bipolar mood stabilizer).
I was thirsty all the time on lithium, & did get the fine hand tremor, which that was not an issue. Being thirsty all the time, I drank a lot of water, & had to get up twice in the night to go to the bathroom. That WAS an issue, since I live in a 2 story farm house, & had to go down stairs. Ny understanding is that lithium works better on people who have had fewer bipolar episodes, & this does bear out in my case - in my 20's, it did help some, but now that I am 44, it just does not help at all. If the lithium stabilized my moods quite a bit, I would have figured out a way to deal with the side effects.
the mental restlessness from risperdal or abilify could have been akasthisia, which antipsychotics can cause. I never heard of anyone complaining about that with lamictal before.
The answer depends on which symptoms r left from ur bipolar - r u mostly sad? Lack of energy? Irritable?
A really good place to read up on options is at bipolarworld.net, click on ask the doctor, & read all the stuff Dr. Phelps has written up. He will address which symptoms the different meds seem to work on, best.
I will be honest with u - very few people with bipolar ever get total symptom remission. Even between relapses, like 80% of us have residual symptoms. Unemployment is over 60%. It is a very serious mental illness to get. Many people get sicker as they get older. Keep working at it though - there r many, many meds to try. Also get psychotherapy - learn to recognize triggers, keep a regular schedule, get regular exercise, learn to reduce stress - these things all help a lot. There r books written up on these topics now, on how to keep yourself more stable when u have bipolar, beyond the needed meds. Meds alone r not enough.
Good luck!