I saw a thing somewhere, a flier or maybe it was a TV ad -- yes, I guess it was a TV ad -- about depression. They had it illustrated like this, that the synapses in your brain were little ovals floating around and there were these energetic connectors between them.
When the connectors were minimal or falling off in number, the poor synapses didn't know what to do, so they became depressed. Rather, it'd be that your mind needs whatever activity they're doing to have its normal feeling. When the connectors were falling off, brain activity went into a funk, or something.
But whatever the medicine is for this restores or re-energizes them or counterfeits them well enough that your mind gets by. Like crutches for walking but it's all mental.
My mentality is very poor today, but I don't have any kind of medicine for such things. It's just a matter of suffer it -- and maybe enjoy it if I can -- and hope it gets better. It will.