[Light spoilers] A character with a cat dies. She had previously mentioned having no family, so one can speculate that her cat is then abandoned after her death. It is not intentional and is not depicted.
The main character at one point says sorry doesn't fix the abuse. She later acknowledges that her mum was a demon when she was drinking but her mum the rest of the time but this isn't forgiveness just acknowledging how things were. The other character who suffered religious abuse at the hands of her parents also doesn't forgive them.
Kinda not really [SPOILER] the doctor gets impaled by the emergency lockdown door as it's closing, but she's pulled out before she's completely crushed
Because it's about a medical trial there are blood tests at various points and such which you see up quite close. There are also quite a few shots of syringes that are intended to inject a sedative and a mixture into 2 people quite far into the film.
[SPOILERS] Several characters began to experience personality changes and hallucinations, which caused them to act out violently towards others. Though the characters aren't portrayed as mentally ill before the trials, they certainly become unstable during it. Some could be triggered by this.
A character repeatedly has flashbacks (some episode related, some seemingly brought on by the medications and/or sleep deprivation) to childhood abuse.
There is talk of being watched from "secret rooms," but the only watchers we are shown are those observing the drug trials (whom the participants are aware of).
There is one moment in which a character jokes that they've never danced with anyone who wasn't "trying to f**k [them]," to which another character jokes back, "The night is still young!" This is entirely lighthearted and is the only sexual moment throughout the film.
Near the end of a movie, a van screeches, swerves, and flips onto its side. The broken windshield is shown along with light blood and an arm (not severed, just limp.)
In general it's quite mild. There are a couple of bloody bits. [spoiler] When you see Allison sitting in a chair facing away from the group and Claire gets up to see if she's okay she then bleeds from her facial features and has a seizure before dying, shortly after that (pretty much the next scene) the doctor is impaled by a door lock as the facility locks down (but not crushed). Later another character is shown after they have also had the same sort of seizure with blood on their face but you don't see it happen. Right after they find him the main character burns her hand and you see the burn. Vanessa also later has the seizure and bleeds and you do see it happen this time. After this another character is stabbed in the neck accidentally when Amir escapes from being tied up, Amir then stabs him repeatedly with a knife. Amir gets shot then Claire spreads his blood on her face to escape, and then there's a car crash with a small amount of blood.