I haven't been on a med yet without side effects -- I don't even remember what they all were.
And I've been on a lot of meds.  One thing a lot of people don't understand is that popping a pill doesn't necessarily solve everything; in fact it rarely does.  I went through years of "80% of people suffering from this are helped by X", but after six months X was helping, so we tried something different -- "75% of people suffering from this who aren't helped by X are helped by Y"... but Y didn't do much at all, so we moved on.
I've had side effects ranging from erections that lasted seven hours (no, it ISN'T kool!) to not being able to tell if I was turning (and, conversely, telling my body to turn and finding it didn't respond, which meant I kept running into walls), to hearing voices, to incredible thirst (how does downing eight liters of water, juices, skim milk, etc. a day but still wanting more strike you?), to tremors, to lack of sexual urges at all, to INCREDIBLE sexual urges....
There are different meds for different things, and not all the interactions are understood, and those can get you in trouble.  I got taken off depakote because of bad interactions with prozac that apparently hit only males!  And the same drug doesn't keep doing the same thing, or do the same thing every time:  I was put on lithium early on, and it stabilized my mood -- at a point where nothing seemed important; now I'm back on it and it's stabilizing my mood at a much happier level (but killing the manic periods that can be so much fun).  Prozac was an enormous relief -- it gave me days at a time without black moods when I felt like if I died, aliens on the other side of the universe would find life more enjoyable but not know why -- but after two years it started being less effective, and then started messing with my mind in a bad way.  Xanax was great for calming me in dark moods, but wow! could it trigger (bad) mania!
Warnings have to be taken seriously.  For teens, they have to be taken MORE seriously, because the brain is rewiring itself, and predicting just what a new substance in the bloodstream will do is a matter requiring watchful concern.
And every professional I've known in mental health has said that the most stablizing factor for someone with a mood disorder is close friends who can be counted on.  The sad thing is how many friends back off when it's "mental illness"!