An addendum to my comments on lithium. There is a very, very fine line between the amount of lithium you need for it to be effective, and the amount of lithium that becomes toxic. Because of that it requires constant vigilance and regular blood tests. It has come to the front of my mind because my recent blood test has shown that my lithium levels are too low and therefore not doing their job, and I've had to raise my dose by 200mg to 1200mg - and is probably why I've been struggling recently.