How long to take lithium as add on for severe recurrent major depression?

Lithium treatment: Lithium can be taken as long as necessary provided it is the primary med necessary to stabilize a person's recurring depression and is medically safe. Blood levels should be drawn periodically to monitor, eg., lithium levels, thyroid, kidney function. Close clinical supervision is essential to observe a pt's functioning and address any side effects, eg. tremor, weight gain which may occur.