Confused with MOA of lithium

Confused with MOA of lithium.
U have taught … 1)it blocks Gq of neurons causing decreased BDNF .
2)inhibits GSK3 causing ultimately increases BDNf synthesis.
When the drug is given …technically it should have no effect of BDNf levels ryt…as it works both ways.
Therfore the name MOOD STABILIZERS is apt for it.
Then how come we are giving for Anti- mania?
But also resistant depression?

It chooses a pathway to block depending upon the levels of BNDF; thus lithium can both increase or decrease BDNF depending upon the need of brain.