I'm no expert but a few minutes of searching came up with these links. They're not all peer reviewed, but the first one is, and pretty much sums up what I'm trying to say. The other articles are about the allged sexual abuse that occurs on set, and a few articles are about the tragic stories of ex-performers who took their own life due to the severe trauma they experienced on set and afterwards.

Again, I'm not saying that all adult content is bad like this. Nothing is black and white like that. I'm saying that a lot of disgusting material is out there and it's possible to watch a video without knowing the story behind it. As such I believe it is a viewer's responsibility to do some research before they enjoy something. A little bit of background about the studio producing a scene is not hard to find and can go a long way to ensure you're enjoying something that nobody had to suffer for.

As an aside: the attitude that "if someone was going to suffer anyways who cares if they suffered for this" is truly a sad way to think.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2629520/

https://www.psychologytoday.com/us/blog/talking-about-trauma/201701/lack-regulation-in-porn-industry-leaves-women-unprotected

https://nypost.com/2018/08/29/i-was-treated-like-a-piece-of-meat-adult-actress-waits-for-metoo/

https://www.mic.com/articles/129866/what-s-going-on-at-kink-com-the-studio-at-the-center-of-the-james-deen-allegations

https://www.thedailybeast.com/accuser-james-deen-had-help-raping-me

https://www.cbsnews.com/news/adult-film-performers-say-the-state-of-mental-health-in-the-industry-needs-more-attention/

https://www.ibtimes.com/ex-porn-star-mia-khalifa-regrets-adult-film-stint-videos-will-haunt-me-until-i-die-2999660

http://www.augustames.com/index.php/blog/

https://nypost.com/2018/01/23/why-porn-stars-are-dying-at-an-alarming-rate/

https://www.news.com.au/lifestyle/real-life/news-life/porn-industry-reeling-after-five-deaths-in-only-three-months/news-story/e779587b387f0ad2b3ae71ec45f0c631