Johann Hari covers a lot of the history of antidepressants in "Lost Connections." Per the studies he covers in the book, most of the benefits are placebo effect. The remainder is somewhat of a mystery. Whether you give someone a medication that increases the level of serotonin in their system (i.e. an SSRI), or that decreases the level of serotonin, the effect will the be same. Replace the drugs targeting serotonin with drugs that target dopamine and you can expect the same effect.
https://www.theguardian.com/books/2018/jan/17/lost-connectio...