How safe is a careful long term use of lithium for bipolar disorder? also, i was always athletic, but could i gain weight when i start lithium?

Lithium safety: First of all, lithium can be very effective and has been credited in saving millions of lives. Used chronically it can cause tremor, more frequent urination, tiredness, weight gain, incoordination, and thyroid issues. It is via hypothyroidism that it also can cause weight gain. Typically blood levels are monitored to assess thyroid, kidney function, and lithium levels.