I have bipolar 1 with psychotic features and I used to take lamotrigine, lithium and a moderate dose of an antipsychotic (olanzapine). Although these meds were supposed to stabilize my mood, I was depressed most of the time. I also gained over 10 kg and the lithium caused me to develop subclinical hypothyroidism. Long term lithium use can also cause kidney failure. So, with the help of my psychiatrist, I came off the lithium.
I'm now on a minuscule dose of an antipsychotic (25 mg quetiapine) and have lost most of the weight I had previously gained. I still take lamotrigine which, along with mindfulness, help with my depression. Lamotrigine has negligible side effects but long term use of antipsychotics is associated with several problems.