Idk about those studies but I know the 'give up' threshold to despair is real. They drown rats and the ones who felt unable to escape allowed themselves to drown even after they were released from the constraint. They theorize this is the same reason officers fall down and bleed out from a relatively non lethal wound, cops and robbers/cowboys and Indians mentality gets drilled in that getting shot means you fall down. Almanac of the strange.
I dont know anything about the effect you mentioned, but the I can explain the bit about wounds.
Bleeding out can occur VERY rapidly. Additionally, the body tends to go into shock if you are wounded bad enough, OR the pain can be so debilitating that you collapse from trying to deal with it.
I encourage you to go online and look up a video of two people having a gun fight with pistols. If you watch enough fatal wounds, you will notice that alot of people who are hit from pistol rounds usually do not die immediately, but still collapse like they are tired. It literally looks like someone who is just tuckered out from running to far. The reality is that blood loss is making them weak. Rifle rounds are a totally different issue. Even grazing rifle rounds can leave enough damage that the wounded person might drop. And hits to anything resembling center mass tend to cause immediate catastrophic damage.
