Not completely clear, but a character declines eating often/most all the time. Katie, the main character tells another character she "doesn't eat" when offered a snack. Later, she explains she doesn't eat to appear more ill.
A character pretends to have a debilitating illness that could be seen as a disability. She does this for attention and financial gain. This puts other people with her illness at a disadvantage as she takes opportunities they can have.
The main character's mother is implied to be dead. Another character's mother dies midway through the movie. Neither death is shown or talked about in detail.
The whole movie is about a character pretending to have cancer. So, technically no. But, cancer is a main subject of the movie and it can be triggering.
Numerous people especially Katie's girlfriend are manipulated into thinking she has a terminal illness. When people call Katie out she tries to gaslight them further. Towards the end the gaslighting becomes more intense.