L. Orotate and serotonin synthesis

At high doses lithium can depress dopamine release (which tends to flatten elevated moods, while at lower doses it can stimulate serotonin synthesis, which gives an antidepressant effect).

[28] Perez-Cruet J, Tagliamonte A, Tagliamonte P, Gessa GL. Stimulation of serotonin synthesis by lithium. J Pharmacol Exp Ther. 1971;178(2):325-30.