Thriller that goes by quick but had me hesitating about depictions of mental illness in the book

As with any good thriller, this book was really hard to put down! This book contains chapters that are written from the perspective of different characters. While the characters are very different, they are all engaging, detail-oriented and relatable. I found the story lightly perplexing (meaning that I often read a page from one character's perspective and then had to flip back and compare it to what was mentioned by another character earlier). I don't think this is a bad thing. The complexity is just enough to leave you wanting to try to put the pieces together but not so severe as to drive you to give up on the puzzle altogether. This book references the realities of life during the pandemic which gives the book a more contemporary feel that I found surprisingly refreshing and relatable. On a separate note, I always hesitate when reading fictional accounts of mental illness. I wonder what research went into depicting the characters. I also wonder how fair the depictions of certain mental illness are to the people who have those specific diagnoses. Absent any deep acknowledgement of these issues in an addendum or prologue, I can't give this book five stars.