Why does lithium therapy work for bipolar disorder?

Whilst it’s been known for years that lithium drugs help many bipolar patients to manage their disorder, it hasn’t been known how lithium acts.  But now there is a clue! Laboratory studies show a link between lithium and an enzyme known as PO*. This enzyme controls a group of genes which affect brain cells’ sensitivity to lithium. And one of those genes, ImpA2, is also associated with bipolar disorder in some sufferers. So possibly there is a functional connection between ImpA2 and bipolar disorder, which can be mediated by lithium. Understanding this link could lead the way to better treatments for bipolar depression.

*PO=prolyl oligopeptidase