Sometimes girls get depressed when their periods start. Girls often don't ovulate regularly, which can cause problems until their cycle stabilizes. Sometimes pediatricians don't allow girls' cycles to stabilize. The doctor says to the girl, "you're a woman now, so we're going to regulate your irregular period with birth control."
Women often get depressed due to the progestins used in all the birth control prescriptions.
SSRIs never help because of boosting serotonin. When someone benefits, it's from the drug's other physiological effects.
It's too early to say. Obviously the idea is to get her off it if possible.
SSRIs never help because of boosting serotonin.
That's a hell of a claim, which could use some evidence.
You understand that the people who sold you that drug have a vested interest in making sure it's not possible and/or that you & she think it's not possible, right?
Usually this takes the form of "I'm prescribing you with <Brand> instead of generic" or "I'm prescribing you this specific drug from this class of drug"