13yr old takes pristiq (desvenlafaxine) for anxiety for the last year, he is a slow metabolizer of the enzyme for all other anti depressants. he just started having days where he is depressed next day he is fine?

Antidepressants: This event should be discussed with the psychiatrist. It is possible that a mood stabilizer would work better (lamotrigine in particular, divalproex, lithium) in regulating the mood up. There is a chance of being bipolar ii (a particular firm of mood disorder) or having add, which also would evidence by drops in mood, due to "exhaustion" of the noradrenergic system. Check with the specialist.