It's unfortunate that SSRIs have harmful long-term effects—I know some people who have been dependent on SSRIs for around a decade, and probably will be forever because of the neurotoxicity.
And to be clear a placebo doesn't mean the effect of such isn't real. Mental state provably affects the body in all sorts of ways. Interestingly enough the placebo effect is often substantially stronger in Americans than in other groups as well [1]. The two main hypothesis there are that more poorly performing drugs are making it past regulators, the other is that the overwhelming amount of direct-to-consumer medical advertising creates a greater faith in the power of pills than in other countries - US/New Zealand are the only developed countries that allow direct to consumer medical ads. Or perhaps a mixture of both, like in many things.
[1] - https://qz.com/525995/why-the-placebo-effect-is-getting-stro...