There is at least one story option that involves the protagonist's dog, an elderly pug named Gretchen, being killed. There is a chance dogs are also involved in the line-up scene of rotting animal carcasses, but I couldn't directly identify any. (There are foxes, however.)
The player can choose between he/him, she/her, and they/them pronouns for the player character. All dialogue referring to the player character will use the selected pronouns.
This is alluded to as a possibility in the background of one character and possibly the protagonist, but no details are ever given and it doesn't come up often.
Depending on what other characters have seen, they may explicitly deny supernatural events experienced together.
Also, a character is implied to be gaslit by their parent.
At least 2-3 characters are implied to have suffered or be suffering some form of emotional, verbal, or physical abuse/manipulation from a parental figure.
As far as I know, as of episode one, the protagonist's cat Frou-Frou does not die. However, in a later scene there is a line-up of decaying, malformed, and slain animals; a few of which appear to be a mountain lion and at least one domestic cat. Poor babies..
There's an event that can involve the death of a character's pet dog depending on choices the player makes, as stated as a response to "Does the dog die?" + a farmer's chickens are being killed by something
If you drink the tea offered to you in Chapter 4, your character can find themselves unable to resist listening to another character telling them to leave.
Depending on choices made in episode 2, it's heavily implied that two people die in a mine collapse. There's also imagery related to a past collapse that resulted in mass casualty.
There are two scenes involving fairly graphic head trauma. One is only encountered if a player makes a certain choice in episode 1, the other is unavoidable but not quite as visually graphic in episode 3.
It's not shown, but at one point, the protagonist (and possibly another character) loses consciousness and another character comments that it seems like they may have had a seizure.
Depending on choices made in episode 3, a character may sacrifice something important. This does not result in death, but is heavily implied to result in impairment.
The entire premise of the game revolves around your character visiting their last surviving relative for her mother's funeral. Also, depending on the choice's made in episode 1, a side character who happens to be a father can die.
A large part of episode 3 revolves around everyone but the player character (and another person, depending on your choices) being possessed by a ghost. If you have the Mystical trait, you can channel the spirit as well.
The phrase 'Post Traumatic Stress Disorder' or 'PTSD' is not explicitly used to my knowledge, but at least one character is heavily implied to have PTSD symptoms.
It's completely optional, but one of the love interests is implied to be ~10 years the protagonist's senior. The protagonist is a young adult, however, most likely early 20s.