The neurotransmitter model of mental illness is largely incorrect. It's much more complex than just "Depressives have less serotonin, therefore lets give a reuptake-inhibitor to keep serotonin in the brain".
My personal preference is to always suggest getting actual daylight on your retina for 20 min three times a week. Not through glasses, including eyeglasses, but can be through eyelids. That loads transferatin, as in transfer, this loads the enzyme that make serotonin. This then allows the body a better chance to make the intermediate between Serotionin and Melatonin, and is the one believed to help. But the patents have expired so it is like an orphan drug now.