Depression, in my opinion, is something most people can overcome. Rather than looking within and learning about themselves, most people would rather just pop a feel-good pill every morning.
And the drugs themselves. They're essentially a bunch of random chemicals that big pharma shoves down the throats of test subjects and looks for good things that could happen. I would rather deal with my mild depression than take pills that could make me nauseous, give headaches, make me bleed from strange places or even kill me. Most people don't weigh the costs and benefits of taking prescription drugs... because it's easier.