It has now been shown that lithium, which is used as a treatment for bipolar disorder, acts as a mood stabilizer by selectively inhibiting GSK-3. The mechanism through which GSK-3 inhibition stabilizes mood is not known, though it is suspected that the inhibition of GSK-3's ability to promote inflammation contributes to the therapeutic effect. Inhibition of GSK-3 also destabilises Rev-ErbA alpha transcriptional repressor, which has a significant role in the circadian clock. Elements of the circadian clock may be connected with predisposition to bipolar mood disorder.