... over time?

I'm asking so that I understand it's okay to take at night.
Someone said "Why take it at night? You're not depressed when you sleep."
But does it really help depression hours after you take it, or does it just make it work days after?

I've been on it now for one week...
It makes me very drowsy when I take it.
I'd like to take it at night, but not if it works hours after taking it. Do you know what I mean?