I know this question is odd, but unfortunately we have a lot of unhoused addicted people in my city. I often see them sitting on a bench bent at the waist in half like a rag doll, or standing somewhere half bent over, like stooped over nodding out I guess? I don't really know anything about substance use, but it's such a strange sight, what substances cause them to bend over like this?
Poor souls. The mayors of big cities here have asked the provincial government to declare a state of emergency due to homelessness and addiction being so rampant, but Doug Ford doesn't give a shit about them.
It is most likely Fentanyl, or some other form of opiate. Prolonged abuse causes them to lose control of their muscles around their core and this is the result.
I used to work near a hot spot for homelessness and drug use in San Francisco and witnessed it everyday. The things these people go through with that addiction are downright horrendous and the "Fentanyl Fold" or "Fent Bent" is actually one of the lesser symptoms. The skin infections, kidney problems, and digestive issues can become pretty severe. I've seen quite a few screaming in agony because their kidneys are messed up and they can't urinate. People with infected swollen hands or feet. You can literally smell them rotting. Too much to list here honestly. It is a terrible drug that does permanent damage to people at best, and is just a slow agonizing death at worst.